21339618 has 16 divisors (see below), whose sum is σ = 43281216. Its totient is φ = 7012880.

The previous prime is 21339599. The next prime is 21339629. The reversal of 21339618 is 81693312.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24621 + ... + 25472.

It is an arithmetic number, because the mean of its divisors is an integer number (2705076).

Almost surely, 2^21339618 is an apocalyptic number.

21339618 is an abundant number, since it is smaller than the sum of its proper divisors (21941598).

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

21339618 is a wasteful number, since it uses less digits than its factorization.

21339618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50169.

The product of its digits is 7776, while the sum is 33.

The square root of 21339618 is about 4619.4824385422. The cubic root of 21339618 is about 277.3717417194.

The spelling of 21339618 in words is "twenty-one million, three hundred thirty-nine thousand, six hundred eighteen".