21599723940 has 24 divisors (see below), whose sum is σ = 60479227200. Its totient is φ = 5759926368.

The previous prime is 21599723909. The next prime is 21599723947. The reversal of 21599723940 is 4932799512.

It is not an unprimeable number, because it can be changed into a prime (21599723947) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 179997640 + ... + 179997759.

It is an arithmetic number, because the mean of its divisors is an integer number (2519967800).

Almost surely, 2^21599723940 is an apocalyptic number.

21599723940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21599723940 is an abundant number, since it is smaller than the sum of its proper divisors (38879503260).

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

21599723940 is a wasteful number, since it uses less digits than its factorization.

21599723940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 359995411 (or 359995409 counting only the distinct ones).

The product of its (nonzero) digits is 1224720, while the sum is 51.

The spelling of 21599723940 in words is "twenty-one billion, five hundred ninety-nine million, seven hundred twenty-three thousand, nine hundred forty".