21306604 has 24 divisors (see below), whose sum is σ = 41545728. Its totient is φ = 9477840.

The previous prime is 21306587. The next prime is 21306617. The reversal of 21306604 is 40660312.

It is a hoax number, since the sum of its digits (22) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3084 + ... + 7219.

It is an arithmetic number, because the mean of its divisors is an integer number (1731072).

Almost surely, 2^21306604 is an apocalyptic number.

It is an amenable number.

21306604 is a deficient number, since it is larger than the sum of its proper divisors (20239124).

21306604 is a wasteful number, since it uses less digits than its factorization.

21306604 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10365 (or 10363 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 22.

The square root of 21306604 is about 4615.9077113825. The cubic root of 21306604 is about 277.2286295510.

Adding to 21306604 its reverse (40660312), we get a palindrome (61966916).

The spelling of 21306604 in words is "twenty-one million, three hundred six thousand, six hundred four".