21018936868 has 12 divisors (see below), whose sum is σ = 37248749440. Its totient is φ = 10376437032.

The previous prime is 21018936857. The next prime is 21018936907. The reversal of 21018936868 is 86863981012.

It is a hoax number, since the sum of its digits (52) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33257496 + ... + 33258127.

Almost surely, 2^21018936868 is an apocalyptic number.

It is an amenable number.

21018936868 is a deficient number, since it is larger than the sum of its proper divisors (16229812572).

21018936868 is a wasteful number, since it uses less digits than its factorization.

21018936868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66515706 (or 66515704 counting only the distinct ones).

The product of its (nonzero) digits is 995328, while the sum is 52.

The spelling of 21018936868 in words is "twenty-one billion, eighteen million, nine hundred thirty-six thousand, eight hundred sixty-eight".