21715248 has 20 divisors (see below), whose sum is σ = 56097848. Its totient is φ = 7238400.

The previous prime is 21715247. The next prime is 21715249. The reversal of 21715248 is 84251712.

It is an interprime number because it is at equal distance from previous prime (21715247) and next prime (21715249).

It is not an unprimeable number, because it can be changed into a prime (21715247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 226153 + ... + 226248.

Almost surely, 2^21715248 is an apocalyptic number.

It is an amenable number.

21715248 is an abundant number, since it is smaller than the sum of its proper divisors (34382600).

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

21715248 is a wasteful number, since it uses less digits than its factorization.

21715248 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 452412 (or 452406 counting only the distinct ones).

The product of its digits is 4480, while the sum is 30.

The square root of 21715248 is about 4659.9622316066. The cubic root of 21715248 is about 278.9897608041.

Subtracting 21715248 from its reverse (84251712), we obtain a square (62536464 = 7908²).

The spelling of 21715248 in words is "twenty-one million, seven hundred fifteen thousand, two hundred forty-eight".