21307502331 has 8 divisors (see below), whose sum is σ = 31566670160. Its totient is φ = 14205001536.

The previous prime is 21307502327. The next prime is 21307502383. The reversal of 21307502331 is 13320570312.

21307502331 is a `hidden beast` number, since 21 + 307 + 5 + 0 + 2 + 331 = 666.

It is not a de Polignac number, because 21307502331 - 2² = 21307502327 is a prime.

It is a super-2 number, since 2×21307502331² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 789166753 = 21307502331 / (2 + 1 + 3 + 0 + 7 + 5 + 0 + 2 + 3 + 3 + 1).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21307502295 and 21307502304.

It is not an unprimeable number, because it can be changed into a prime (21307506331) 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, 394583350 + ... + 394583403.

It is an arithmetic number, because the mean of its divisors is an integer number (3945833770).

Almost surely, 2^21307502331 is an apocalyptic number.

21307502331 is a deficient number, since it is larger than the sum of its proper divisors (10259167829).

21307502331 is an equidigital number, since it uses as much as digits as its factorization.

21307502331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 789166762 (or 789166756 counting only the distinct ones).

The product of its (nonzero) digits is 3780, while the sum is 27.

The spelling of 21307502331 in words is "twenty-one billion, three hundred seven million, five hundred two thousand, three hundred thirty-one".