21312057858 has 64 divisors (see below), whose sum is σ = 52492000512. Its totient is φ = 5617382400.

The previous prime is 21312057857. The next prime is 21312057869. The reversal of 21312057858 is 85875021312.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (21312057857) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 972510 + ... + 994182.

It is an arithmetic number, because the mean of its divisors is an integer number (820187508).

Almost surely, 2^21312057858 is an apocalyptic number.

21312057858 is an abundant number, since it is smaller than the sum of its proper divisors (31179942654).

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

21312057858 is a wasteful number, since it uses less digits than its factorization.

21312057858 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23499.

The product of its (nonzero) digits is 134400, while the sum is 42.

The spelling of 21312057858 in words is "twenty-one billion, three hundred twelve million, fifty-seven thousand, eight hundred fifty-eight".