21081685392 has 60 divisors (see below), whose sum is σ = 59026378320. Its totient is φ = 7024019904.

The previous prime is 21081685381. The next prime is 21081685399. The reversal of 21081685392 is 29358618012.

21081685392 is a `hidden beast` number, since 2 + 108 + 1 + 6 + 8 + 539 + 2 = 666.

It is not an unprimeable number, because it can be changed into a prime (21081685399) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 294159 + ... + 358737.

It is an arithmetic number, because the mean of its divisors is an integer number (983772972).

Almost surely, 2^21081685392 is an apocalyptic number.

It is an amenable number.

21081685392 is an abundant number, since it is smaller than the sum of its proper divisors (37944692928).

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

21081685392 is a wasteful number, since it uses less digits than its factorization.

21081685392 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66860 (or 66851 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 45.

The spelling of 21081685392 in words is "twenty-one billion, eighty-one million, six hundred eighty-five thousand, three hundred ninety-two".