21648475 has 12 divisors (see below), whose sum is σ = 27170136. Its totient is φ = 17108480.

The previous prime is 21648469. The next prime is 21648481. The reversal of 21648475 is 57484612.

It is an interprime number because it is at equal distance from previous prime (21648469) and next prime (21648481).

It is not a de Polignac number, because 21648475 - 2¹⁷ = 21517403 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3142 + ... + 7291.

It is an arithmetic number, because the mean of its divisors is an integer number (2264178).

Almost surely, 2^21648475 is an apocalyptic number.

21648475 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21648475 is a deficient number, since it is larger than the sum of its proper divisors (5521661).

21648475 is a wasteful number, since it uses less digits than its factorization.

21648475 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10526 (or 10521 counting only the distinct ones).

The product of its digits is 53760, while the sum is 37.

The square root of 21648475 is about 4652.7921724487. The cubic root of 21648475 is about 278.7035086385.

The spelling of 21648475 in words is "twenty-one million, six hundred forty-eight thousand, four hundred seventy-five".