21165310536 has 64 divisors (see below), whose sum is σ = 53676216000. Its totient is φ = 6954105600.

The previous prime is 21165310513. The next prime is 21165310541. The reversal of 21165310536 is 63501356112.

It is a junction number, because it is equal to n+sod(n) for n = 21165310497 and 21165310506.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 445866 + ... + 491046.

It is an arithmetic number, because the mean of its divisors is an integer number (838690875).

Almost surely, 2^21165310536 is an apocalyptic number.

It is an amenable number.

21165310536 is an abundant number, since it is smaller than the sum of its proper divisors (32510905464).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21165310536 is a wasteful number, since it uses less digits than its factorization.

21165310536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45470 (or 45466 counting only the distinct ones).

The product of its (nonzero) digits is 16200, while the sum is 33.

Adding to 21165310536 its reverse (63501356112), we get a palindrome (84666666648).

The spelling of 21165310536 in words is "twenty-one billion, one hundred sixty-five million, three hundred ten thousand, five hundred thirty-six".