21658138432 has 56 divisors (see below), whose sum is σ = 50162667264. Its totient is φ = 9084559872.

The previous prime is 21658138423. The next prime is 21658138451. The reversal of 21658138432 is 23483185612.

It is a tau number, because it is divible by the number of its divisors (56).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 493243 + ... + 535354.

Almost surely, 2^21658138432 is an apocalyptic number.

It is an amenable number.

21658138432 is an abundant number, since it is smaller than the sum of its proper divisors (28504528832).

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

21658138432 is a wasteful number, since it uses less digits than its factorization.

21658138432 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1028663 (or 1028653 counting only the distinct ones).

The product of its digits is 276480, while the sum is 43.

The spelling of 21658138432 in words is "twenty-one billion, six hundred fifty-eight million, one hundred thirty-eight thousand, four hundred thirty-two".