21958472 has 16 divisors (see below), whose sum is σ = 41598060. Its totient is φ = 10865664.

The previous prime is 21958459. The next prime is 21958477. The reversal of 21958472 is 27485912.

It can be written as a sum of positive squares in 2 ways, for example, as 20484676 + 1473796 = 4526^2 + 1214^2 .

It is not an unprimeable number, because it can be changed into a prime (21958477) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13373 + ... + 14924.

Almost surely, 2^21958472 is an apocalyptic number.

It is an amenable number.

21958472 is a deficient number, since it is larger than the sum of its proper divisors (19639588).

21958472 is a wasteful number, since it uses less digits than its factorization.

21958472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28400 (or 28396 counting only the distinct ones).

The product of its digits is 40320, while the sum is 38.

The square root of 21958472 is about 4685.9867690808. The cubic root of 21958472 is about 280.0275143030.

The spelling of 21958472 in words is "twenty-one million, nine hundred fifty-eight thousand, four hundred seventy-two".