21680957694 has 32 divisors (see below), whose sum is σ = 47528127360. Its totient is φ = 6538845600.

The previous prime is 21680957663. The next prime is 21680957759. The reversal of 21680957694 is 49675908612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 764509 + ... + 792360.

It is an arithmetic number, because the mean of its divisors is an integer number (1485253980).

Almost surely, 2^21680957694 is an apocalyptic number.

21680957694 is an abundant number, since it is smaller than the sum of its proper divisors (25847169666).

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

21680957694 is a wasteful number, since it uses less digits than its factorization.

21680957694 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1557096.

The product of its (nonzero) digits is 6531840, while the sum is 57.

The spelling of 21680957694 in words is "twenty-one billion, six hundred eighty million, nine hundred fifty-seven thousand, six hundred ninety-four".