21578887612 has 24 divisors (see below), whose sum is σ = 38795687280. Its totient is φ = 10495923840.

The previous prime is 21578887609. The next prime is 21578887657. The reversal of 21578887612 is 21678887512.

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, 132687 + ... + 246502.

It is an arithmetic number, because the mean of its divisors is an integer number (1616486970).

Almost surely, 2^21578887612 is an apocalyptic number.

It is an amenable number.

21578887612 is a deficient number, since it is larger than the sum of its proper divisors (17216799668).

21578887612 is a wasteful number, since it uses less digits than its factorization.

21578887612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 379581 (or 379579 counting only the distinct ones).

The product of its digits is 3010560, while the sum is 55.

The spelling of 21578887612 in words is "twenty-one billion, five hundred seventy-eight million, eight hundred eighty-seven thousand, six hundred twelve".