21945884 has 24 divisors (see below), whose sum is σ = 39963840. Its totient is φ = 10535616.

The previous prime is 21945881. The next prime is 21945907. The reversal of 21945884 is 48854912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21945881) 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, 10754 + ... + 12630.

It is an arithmetic number, because the mean of its divisors is an integer number (1665160).

Almost surely, 2^21945884 is an apocalyptic number.

It is an amenable number.

21945884 is a deficient number, since it is larger than the sum of its proper divisors (18017956).

21945884 is a wasteful number, since it uses less digits than its factorization.

21945884 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1997 (or 1995 counting only the distinct ones).

The product of its digits is 92160, while the sum is 41.

The square root of 21945884 is about 4684.6434229299. The cubic root of 21945884 is about 279.9739941833.

The spelling of 21945884 in words is "twenty-one million, nine hundred forty-five thousand, eight hundred eighty-four".