21157078392 has 64 divisors (see below), whose sum is σ = 58850937600. Its totient is φ = 7042606560.

The previous prime is 21157078361. The next prime is 21157078409. The reversal of 21157078392 is 29387075112.

21157078392 is a `hidden beast` number, since 2 + 1 + 1 + 570 + 78 + 3 + 9 + 2 = 666.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 89667 + ... + 224397.

It is an arithmetic number, because the mean of its divisors is an integer number (919545900).

Almost surely, 2^21157078392 is an apocalyptic number.

It is an amenable number.

21157078392 is an abundant number, since it is smaller than the sum of its proper divisors (37693859208).

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

21157078392 is a wasteful number, since it uses less digits than its factorization.

21157078392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135473 (or 135463 counting only the distinct ones).

The product of its (nonzero) digits is 211680, while the sum is 45.

The spelling of 21157078392 in words is "twenty-one billion, one hundred fifty-seven million, seventy-eight thousand, three hundred ninety-two".