21204064253 has 2 divisors, whose sum is σ = 21204064254. Its totient is φ = 21204064252.

The previous prime is 21204064247. The next prime is 21204064307. The reversal of 21204064253 is 35246040212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18397395769 + 2806668484 = 135637^2 + 52978^2 .

It is a cyclic number.

It is not a de Polignac number, because 21204064253 - 2²² = 21199869949 is a prime.

It is a super-2 number, since 2×21204064253² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21204064753) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10602032126 + 10602032127.

It is an arithmetic number, because the mean of its divisors is an integer number (10602032127).

Almost surely, 2^21204064253 is an apocalyptic number.

It is an amenable number.

21204064253 is a deficient number, since it is larger than the sum of its proper divisors (1).

21204064253 is an equidigital number, since it uses as much as digits as its factorization.

21204064253 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11520, while the sum is 29.

The spelling of 21204064253 in words is "twenty-one billion, two hundred four million, sixty-four thousand, two hundred fifty-three".