21857996 has 12 divisors (see below), whose sum is σ = 39570720. Its totient is φ = 10552080.

The previous prime is 21857993. The next prime is 21858017. The reversal of 21857996 is 69975812.

It is a self number, because there is not a number n which added to its sum of digits gives 21857996.

It is not an unprimeable number, because it can be changed into a prime (21857993) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 94100 + ... + 94331.

It is an arithmetic number, because the mean of its divisors is an integer number (3297560).

Almost surely, 2^21857996 is an apocalyptic number.

It is an amenable number.

21857996 is a deficient number, since it is larger than the sum of its proper divisors (17712724).

21857996 is a wasteful number, since it uses less digits than its factorization.

21857996 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 188464 (or 188462 counting only the distinct ones).

The product of its digits is 272160, while the sum is 47.

The square root of 21857996 is about 4675.2535760106. The cubic root of 21857996 is about 279.5997512624.

The spelling of 21857996 in words is "twenty-one million, eight hundred fifty-seven thousand, nine hundred ninety-six".