21906444 has 24 divisors (see below), whose sum is σ = 58417408. Its totient is φ = 6258960.

The previous prime is 21906413. The next prime is 21906461. The reversal of 21906444 is 44460912.

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, 130312 + ... + 130479.

Almost surely, 2^21906444 is an apocalyptic number.

It is an amenable number.

21906444 is an abundant number, since it is smaller than the sum of its proper divisors (36510964).

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

21906444 is a wasteful number, since it uses less digits than its factorization.

21906444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 260805 (or 260803 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 30.

The square root of 21906444 is about 4680.4320313407. The cubic root of 21906444 is about 279.8061753834.

The spelling of 21906444 in words is "twenty-one million, nine hundred six thousand, four hundred forty-four".