21153664446544 has 20 divisors (see below), whose sum is σ = 46840256989024. Its totient is φ = 9065856191328.

The previous prime is 21153664446527. The next prime is 21153664446569. The reversal of 21153664446544 is 44564446635112.

It is a congruent number.

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, 94436001882 + ... + 94436002105.

Almost surely, 2^{21153664446544} is an apocalyptic number.

It is an amenable number.

21153664446544 is an abundant number, since it is smaller than the sum of its proper divisors (25686592542480).

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

21153664446544 is a wasteful number, since it uses less digits than its factorization.

21153664446544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188872004002 (or 188872003996 counting only the distinct ones).

The product of its digits is 33177600, while the sum is 55.

The spelling of 21153664446544 in words is "twenty-one trillion, one hundred fifty-three billion, six hundred sixty-four million, four hundred forty-six thousand, five hundred forty-four".