21113618 has 16 divisors (see below), whose sum is σ = 32133024. Its totient is φ = 10404000.

The previous prime is 21113611. The next prime is 21113629. The reversal of 21113618 is 81631112.

It is a junction number, because it is equal to n+sod(n) for n = 21113593 and 21113602.

It is not an unprimeable number, because it can be changed into a prime (21113611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 68621 + ... + 68927.

It is an arithmetic number, because the mean of its divisors is an integer number (2008314).

Almost surely, 2^21113618 is an apocalyptic number.

21113618 is a deficient number, since it is larger than the sum of its proper divisors (11019406).

21113618 is a wasteful number, since it uses less digits than its factorization.

21113618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 697.

The product of its digits is 288, while the sum is 23.

The square root of 21113618 is about 4594.9557125178. The cubic root of 21113618 is about 276.3890840211.

The spelling of 21113618 in words is "twenty-one million, one hundred thirteen thousand, six hundred eighteen".