21907404 has 36 divisors (see below), whose sum is σ = 56877184. Its totient is φ = 7104672.

The previous prime is 21907397. The next prime is 21907429. The reversal of 21907404 is 40470912.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (36).

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 11 ways as a sum of consecutive naturals, for example, 6892 + ... + 9555.

Almost surely, 2^21907404 is an apocalyptic number.

It is an amenable number.

21907404 is an abundant number, since it is smaller than the sum of its proper divisors (34969780).

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

21907404 is a wasteful number, since it uses less digits than its factorization.

21907404 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16494 (or 16489 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 21907404 is about 4680.5345848525. The cubic root of 21907404 is about 279.8102626131.

The spelling of 21907404 in words is "twenty-one million, nine hundred seven thousand, four hundred four".