21457948 has 6 divisors (see below), whose sum is σ = 37551416. Its totient is φ = 10728972.

The previous prime is 21457939. The next prime is 21457957. The reversal of 21457948 is 84975412.

It is an interprime number because it is at equal distance from previous prime (21457939) and next prime (21457957).

It is a self number, because there is not a number n which added to its sum of digits gives 21457948.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2682240 + ... + 2682247.

Almost surely, 2^21457948 is an apocalyptic number.

It is an amenable number.

21457948 is a deficient number, since it is larger than the sum of its proper divisors (16093468).

21457948 is a wasteful number, since it uses less digits than its factorization.

21457948 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5364491 (or 5364489 counting only the distinct ones).

The product of its digits is 80640, while the sum is 40.

The square root of 21457948 is about 4632.2724444920. The cubic root of 21457948 is about 277.8834803172.

The spelling of 21457948 in words is "twenty-one million, four hundred fifty-seven thousand, nine hundred forty-eight".