21500236314657 has 8 divisors (see below), whose sum is σ = 31852201947680. Its totient is φ = 14333490876420.

The previous prime is 21500236314649. The next prime is 21500236314671. The reversal of 21500236314657 is 75641363200512.

21500236314657 is a `hidden beast` number, since 2 + 1 + 5 + 0 + 0 + 2 + 3 + 631 + 4 + 6 + 5 + 7 = 666.

It is not a de Polignac number, because 21500236314657 - 2³ = 21500236314649 is a prime.

It is a super-2 number, since 2×21500236314657² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21500236314647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 398152524319 + ... + 398152524372.

It is an arithmetic number, because the mean of its divisors is an integer number (3981525243460).

Almost surely, 2^{21500236314657} is an apocalyptic number.

21500236314657 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21500236314657 is a deficient number, since it is larger than the sum of its proper divisors (10351965633023).

21500236314657 is an equidigital number, since it uses as much as digits as its factorization.

21500236314657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 796305048700 (or 796305048694 counting only the distinct ones).

The product of its (nonzero) digits is 907200, while the sum is 45.

The spelling of 21500236314657 in words is "twenty-one trillion, five hundred billion, two hundred thirty-six million, three hundred fourteen thousand, six hundred fifty-seven".