21842904 has 16 divisors (see below), whose sum is σ = 54607320. Its totient is φ = 7280960.

The previous prime is 21842903. The next prime is 21842917. The reversal of 21842904 is 40924812.

It is a super-2 number, since 2×21842904² = 954224910306432, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21842903) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 455037 + ... + 455084.

Almost surely, 2^21842904 is an apocalyptic number.

21842904 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21842904 is an abundant number, since it is smaller than the sum of its proper divisors (32764416).

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

21842904 is a wasteful number, since it uses less digits than its factorization.

21842904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 910130 (or 910126 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 21842904 is about 4673.6392672092. The cubic root of 21842904 is about 279.5353859382.

The spelling of 21842904 in words is "twenty-one million, eight hundred forty-two thousand, nine hundred four".