21277 has 2 divisors, whose sum is σ = 21278. Its totient is φ = 21276.

The previous prime is 21269. The next prime is 21283. The reversal of 21277 is 77212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12996 + 8281 = 114^2 + 91^2 .

It is a cyclic number.

It is not a de Polignac number, because 21277 - 2³ = 21269 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10638 + 10639.

It is an arithmetic number, because the mean of its divisors is an integer number (10639).

2²¹²⁷⁷ is an apocalyptic number.

It is an amenable number.

21277 is a deficient number, since it is larger than the sum of its proper divisors (1).

21277 is an equidigital number, since it uses as much as digits as its factorization.

21277 is an evil number, because the sum of its binary digits is even.

The product of its digits is 196, while the sum is 19.

The square root of 21277 is about 145.8663772087. The cubic root of 21277 is about 27.7100173598.

Adding to 21277 its reverse (77212), we get a palindrome (98489).

It can be divided in two parts, 212 and 77, that added together give a square (289 = 17²).

The spelling of 21277 in words is "twenty-one thousand, two hundred seventy-seven", and thus it is an iban number.