21519476868 has 12 divisors (see below), whose sum is σ = 50212112720. Its totient is φ = 7173158952.

The previous prime is 21519476857. The next prime is 21519476873. The reversal of 21519476868 is 86867491512.

It is a tau number, because it is divible by the number of its divisors (12).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 896644858 + ... + 896644881.

Almost surely, 2^21519476868 is an apocalyptic number.

It is an amenable number.

21519476868 is an abundant number, since it is smaller than the sum of its proper divisors (28692635852).

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

21519476868 is a wasteful number, since it uses less digits than its factorization.

21519476868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1793289746 (or 1793289744 counting only the distinct ones).

The product of its digits is 5806080, while the sum is 57.

The spelling of 21519476868 in words is "twenty-one billion, five hundred nineteen million, four hundred seventy-six thousand, eight hundred sixty-eight".