21054646636 has 12 divisors (see below), whose sum is σ = 36847926360. Its totient is φ = 10526667680.

The previous prime is 21054646609. The next prime is 21054646699. The reversal of 21054646636 is 63664645012.

It is a super-2 number, since 2×21054646636² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21054646592 and 21054646601.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 87721 + ... + 223168.

It is an arithmetic number, because the mean of its divisors is an integer number (3070660530).

Almost surely, 2^21054646636 is an apocalyptic number.

It is an amenable number.

21054646636 is a deficient number, since it is larger than the sum of its proper divisors (15793279724).

21054646636 is a wasteful number, since it uses less digits than its factorization.

21054646636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 327824 (or 327822 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 43.

The spelling of 21054646636 in words is "twenty-one billion, fifty-four million, six hundred forty-six thousand, six hundred thirty-six".