21953872 has 20 divisors (see below), whose sum is σ = 43339860. Its totient is φ = 10769408.

The previous prime is 21953861. The next prime is 21953881. The reversal of 21953872 is 27835912.

It can be written as a sum of positive squares in 2 ways, for example, as 18870336 + 3083536 = 4344^2 + 1756^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12097 + ... + 13792.

It is an arithmetic number, because the mean of its divisors is an integer number (2166993).

Almost surely, 2^21953872 is an apocalyptic number.

It is an amenable number.

21953872 is a deficient number, since it is larger than the sum of its proper divisors (21385988).

21953872 is a wasteful number, since it uses less digits than its factorization.

21953872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25950 (or 25944 counting only the distinct ones).

The product of its digits is 30240, while the sum is 37.

The square root of 21953872 is about 4685.4959182567. The cubic root of 21953872 is about 280.0079589574.

The spelling of 21953872 in words is "twenty-one million, nine hundred fifty-three thousand, eight hundred seventy-two".