21156630544 has 20 divisors (see below), whose sum is σ = 46846825024. Its totient is φ = 9067127328.

The previous prime is 21156630499. The next prime is 21156630553. The reversal of 21156630544 is 44503665112.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 94449132 + ... + 94449355.

Almost surely, 2^21156630544 is an apocalyptic number.

It is an amenable number.

21156630544 is an abundant number, since it is smaller than the sum of its proper divisors (25690194480).

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

21156630544 is a wasteful number, since it uses less digits than its factorization.

21156630544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188898502 (or 188898496 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 37.

The spelling of 21156630544 in words is "twenty-one billion, one hundred fifty-six million, six hundred thirty thousand, five hundred forty-four".