21376618 has 12 divisors (see below), whose sum is σ = 32564322. Its totient is φ = 10524360.

The previous prime is 21376613. The next prime is 21376627. The reversal of 21376618 is 81667312.

It can be written as a sum of positive squares in only one way, i.e., 21372129 + 4489 = 4623^2 + 67^2 .

It is not an unprimeable number, because it can be changed into a prime (21376613) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7788 + ... + 10168.

Almost surely, 2^21376618 is an apocalyptic number.

21376618 is a deficient number, since it is larger than the sum of its proper divisors (11187704).

21376618 is an equidigital number, since it uses as much as digits as its factorization.

21376618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2517 (or 2450 counting only the distinct ones).

The product of its digits is 12096, while the sum is 34.

The square root of 21376618 is about 4623.4854817551. The cubic root of 21376618 is about 277.5319574699.

The spelling of 21376618 in words is "twenty-one million, three hundred seventy-six thousand, six hundred eighteen".