21521120313 has 64 divisors (see below), whose sum is σ = 37764864000. Its totient is φ = 10794127680.

The previous prime is 21521120303. The next prime is 21521120329. The reversal of 21521120313 is 31302112512.

It is not a de Polignac number, because 21521120313 - 2⁵ = 21521120281 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a self number, because there is not a number n which added to its sum of digits gives 21521120313.

It is not an unprimeable number, because it can be changed into a prime (21521120303) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 295470 + ... + 361032.

It is an arithmetic number, because the mean of its divisors is an integer number (590076000).

Almost surely, 2^21521120313 is an apocalyptic number.

It is an amenable number.

21521120313 is a deficient number, since it is larger than the sum of its proper divisors (16243743687).

21521120313 is a wasteful number, since it uses less digits than its factorization.

21521120313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65627 (or 65613 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 21.

Adding to 21521120313 its reverse (31302112512), we get a palindrome (52823232825).

The spelling of 21521120313 in words is "twenty-one billion, five hundred twenty-one million, one hundred twenty thousand, three hundred thirteen".