21900856253 has 2 divisors, whose sum is σ = 21900856254. Its totient is φ = 21900856252.

The previous prime is 21900856213. The next prime is 21900856267. The reversal of 21900856253 is 35265800912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19832243929 + 2068612324 = 140827^2 + 45482^2 .

It is a cyclic number.

It is not a de Polignac number, because 21900856253 - 2²² = 21896661949 is a prime.

It is a super-2 number, since 2×21900856253² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21900856253.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21900856213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10950428126 + 10950428127.

It is an arithmetic number, because the mean of its divisors is an integer number (10950428127).

Almost surely, 2^21900856253 is an apocalyptic number.

It is an amenable number.

21900856253 is a deficient number, since it is larger than the sum of its proper divisors (1).

21900856253 is an equidigital number, since it uses as much as digits as its factorization.

21900856253 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 129600, while the sum is 41.

The spelling of 21900856253 in words is "twenty-one billion, nine hundred million, eight hundred fifty-six thousand, two hundred fifty-three".