21931248 has 20 divisors (see below), whose sum is σ = 56655848. Its totient is φ = 7310400.

The previous prime is 21931243. The next prime is 21931253. The reversal of 21931248 is 84213912.

It is an interprime number because it is at equal distance from previous prime (21931243) and next prime (21931253).

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21931243) 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, 228403 + ... + 228498.

Almost surely, 2^21931248 is an apocalyptic number.

It is an amenable number.

21931248 is an abundant number, since it is smaller than the sum of its proper divisors (34724600).

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

21931248 is a wasteful number, since it uses less digits than its factorization.

21931248 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 456912 (or 456906 counting only the distinct ones).

The product of its digits is 3456, while the sum is 30.

The square root of 21931248 is about 4683.0810370951. The cubic root of 21931248 is about 279.9117408902.

The spelling of 21931248 in words is "twenty-one million, nine hundred thirty-one thousand, two hundred forty-eight".