21311020252 has 12 divisors (see below), whose sum is σ = 37300450936. Its totient is φ = 10653748560.

The previous prime is 21311020229. The next prime is 21311020253. The reversal of 21311020252 is 25202011312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21311020253) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 412983 + ... + 461710.

Almost surely, 2^21311020252 is an apocalyptic number.

It is an amenable number.

21311020252 is a deficient number, since it is larger than the sum of its proper divisors (15989430684).

21311020252 is a wasteful number, since it uses less digits than its factorization.

21311020252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 880788 (or 880786 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 19.

Adding to 21311020252 its reverse (25202011312), we get a palindrome (46513031564).

The spelling of 21311020252 in words is "twenty-one billion, three hundred eleven million, twenty thousand, two hundred fifty-two".