21840204 has 24 divisors (see below), whose sum is σ = 51036160. Its totient is φ = 7269264.

The previous prime is 21840199. The next prime is 21840209. The reversal of 21840204 is 40204812.

It is an interprime number because it is at equal distance from previous prime (21840199) and next prime (21840209).

It is not an unprimeable number, because it can be changed into a prime (21840209) 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, 14637 + ... + 16059.

Almost surely, 2^21840204 is an apocalyptic number.

It is an amenable number.

21840204 is an abundant number, since it is smaller than the sum of its proper divisors (29195956).

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

21840204 is a wasteful number, since it uses less digits than its factorization.

21840204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2709 (or 2707 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 21.

The square root of 21840204 is about 4673.3504041533. The cubic root of 21840204 is about 279.5238676797.

The spelling of 21840204 in words is "twenty-one million, eight hundred forty thousand, two hundred four".