21857175892 has 12 divisors (see below), whose sum is σ = 38314564596. Its totient is φ = 10910157440.

The previous prime is 21857175881. The next prime is 21857175919. The reversal of 21857175892 is 29857175812.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 4673636496 + 17183539396 = 68364^2 + 131086^2 .

It is a super-2 number, since 2×21857175892² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4604959 + ... + 4609702.

It is an arithmetic number, because the mean of its divisors is an integer number (3192880383).

Almost surely, 2^21857175892 is an apocalyptic number.

It is an amenable number.

21857175892 is a deficient number, since it is larger than the sum of its proper divisors (16457388704).

21857175892 is a wasteful number, since it uses less digits than its factorization.

21857175892 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9215258 (or 9215256 counting only the distinct ones).

The product of its digits is 2822400, while the sum is 55.

The spelling of 21857175892 in words is "twenty-one billion, eight hundred fifty-seven million, one hundred seventy-five thousand, eight hundred ninety-two".