21804606 has 32 divisors (see below), whose sum is σ = 48690720. Its totient is φ = 7232832.

The previous prime is 21804539. The next prime is 21804623. The reversal of 21804606 is 60640812.

It is a hoax number, since the sum of its digits (27) 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 (27).

It is a self number, because there is not a number n which added to its sum of digits gives 21804606.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11716 + ... + 13448.

It is an arithmetic number, because the mean of its divisors is an integer number (1521585).

Almost surely, 2^21804606 is an apocalyptic number.

21804606 is an abundant number, since it is smaller than the sum of its proper divisors (26886114).

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

21804606 is a wasteful number, since it uses less digits than its factorization.

21804606 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1977 (or 1971 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 21804606 is about 4669.5402343271. The cubic root of 21804606 is about 279.3719169967.

It can be divided in two parts, 2180 and 4606, that added together give a triangular number (6786 = T₁₁₆).

The spelling of 21804606 in words is "twenty-one million, eight hundred four thousand, six hundred six".