21488372 has 12 divisors (see below), whose sum is σ = 37662660. Its totient is φ = 10727616.

The previous prime is 21488359. The next prime is 21488381. The reversal of 21488372 is 27388412.

It can be written as a sum of positive squares in 2 ways, for example, as 1094116 + 20394256 = 1046^2 + 4516^2 .

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, 953 + ... + 6624.

It is an arithmetic number, because the mean of its divisors is an integer number (3138555).

Almost surely, 2^21488372 is an apocalyptic number.

It is an amenable number.

21488372 is a deficient number, since it is larger than the sum of its proper divisors (16174288).

21488372 is a wasteful number, since it uses less digits than its factorization.

21488372 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8290 (or 8288 counting only the distinct ones).

The product of its digits is 21504, while the sum is 35.

The square root of 21488372 is about 4635.5551986790. Note that the first 3 decimals coincide. The cubic root of 21488372 is about 278.0147500067.

The spelling of 21488372 in words is "twenty-one million, four hundred eighty-eight thousand, three hundred seventy-two".