21552575 has 24 divisors (see below), whose sum is σ = 29383536. Its totient is φ = 15552000.

The previous prime is 21552571. The next prime is 21552607. The reversal of 21552575 is 57525512.

It is not a de Polignac number, because 21552575 - 2² = 21552571 is a prime.

It is a Smith number, since the sum of its digits (32) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21552571) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 49559 + ... + 49991.

It is an arithmetic number, because the mean of its divisors is an integer number (1224314).

Almost surely, 2^21552575 is an apocalyptic number.

21552575 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21552575 is a deficient number, since it is larger than the sum of its proper divisors (7830961).

21552575 is a wasteful number, since it uses less digits than its factorization.

21552575 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 635 (or 630 counting only the distinct ones).

The product of its digits is 17500, while the sum is 32.

The square root of 21552575 is about 4642.4750941712. The cubic root of 21552575 is about 278.2913590434.

The spelling of 21552575 in words is "twenty-one million, five hundred fifty-two thousand, five hundred seventy-five".