1427

This number is a prime.

The smallest four-digit prime such that the following form is also prime: 142⁷ + 14²⁷ + 1⁴²⁷. [Patterson]

The smallest increasing concatenation of 1^1 then 2^2 then...then n^n that is prime, starting with 1. [Patterson]

The smallest prime starting with a composite number and followed by its prime factors. [Firoozbakht]

There are exactly 1427 amicable pairs whose members have ten or less digits. Note that 1427 itself belongs both to a twin prime pair (1427, 1429) and to a cousin prime pair (1423, 1427). [Beedassy]

The smallest prime whose the concatenation of the first two digits is equal to the product of the other digits (14 = 2*7). [Loungrides]

The smallest positive integer whose sum of substrings of digits (142+427+14+42+27+1+4+2+7) is the beast number. [Gaydos]

The admission number of the celebrated French poet Arthur Rimbaud to the "Hôpital de la Conception" (Marseille), where he had the right leg amputated for osteosarcoma. [Olry]

Smallest prime formed by concatenating the self powers of numbers, i.e., 1^1, 2^2 , 3^3, ... . [Sariyar]

There are exactly 1427 fours in the first 1427 fourth powers. [Gaydos]

The second hand occurs midway between hour and minute hands 1427 times every twelve hours. [Gupta]

The only known prime formed by the concatenation of the first terms in the Pillai sequence. Note that the concatenation of two Turkish cities, Sivas and Ankara, form a substring of his middle name (Subbayya Sivasankaranarayana Pillai). [Sariyar]

Milad Tower in Tehran stands 1427 feet tall and is the tallest tower in Iran. [Motamedi]

Ordered concatenation of the first three powers d^d, i.e., 1¹||2²||3³ = 1427. [Loungrides]