21643336756 has 12 divisors (see below), whose sum is σ = 38126673760. Its totient is φ = 10750001400.

The previous prime is 21643336721. The next prime is 21643336787. The reversal of 21643336756 is 65763334612.

It is a happy number.

It is a hoax number, since the sum of its digits (46) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17916066 + ... + 17917273.

Almost surely, 2^21643336756 is an apocalyptic number.

It is an amenable number.

21643336756 is a deficient number, since it is larger than the sum of its proper divisors (16483337004).

21643336756 is a wasteful number, since it uses less digits than its factorization.

21643336756 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35833494 (or 35833492 counting only the distinct ones).

The product of its digits is 1632960, while the sum is 46.

The spelling of 21643336756 in words is "twenty-one billion, six hundred forty-three million, three hundred thirty-six thousand, seven hundred fifty-six".