21663563044644 has 36 divisors (see below), whose sum is σ = 55191859666944. Its totient is φ = 7164327934512.

The previous prime is 21663563044631. The next prime is 21663563044667. The reversal of 21663563044644 is 44644036536612.

21663563044644 is a `hidden beast` number, since 2 + 16 + 6 + 3 + 563 + 0 + 4 + 4 + 64 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2369151492 + ... + 2369160635.

Almost surely, 2^{21663563044644} is an apocalyptic number.

It is an amenable number.

21663563044644 is an abundant number, since it is smaller than the sum of its proper divisors (33528296622300).

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

21663563044644 is a wasteful number, since it uses less digits than its factorization.

21663563044644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4738312264 (or 4738312259 counting only the distinct ones).

The product of its (nonzero) digits is 29859840, while the sum is 54.

The spelling of 21663563044644 in words is "twenty-one trillion, six hundred sixty-three billion, five hundred sixty-three million, forty-four thousand, six hundred forty-four".