21973525 has 24 divisors (see below), whose sum is σ = 31317440. Its totient is φ = 14981760.

The previous prime is 21973463. The next prime is 21973529. The reversal of 21973525 is 52537912.

It is not a de Polignac number, because 21973525 - 2¹⁵ = 21940757 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21973529) 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, 53521 + ... + 53929.

Almost surely, 2^21973525 is an apocalyptic number.

21973525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21973525 is a deficient number, since it is larger than the sum of its proper divisors (9343915).

21973525 is a wasteful number, since it uses less digits than its factorization.

21973525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 733 (or 728 counting only the distinct ones).

The product of its digits is 18900, while the sum is 34.

The square root of 21973525 is about 4687.5926657507. The cubic root of 21973525 is about 280.0914879609.

The spelling of 21973525 in words is "twenty-one million, nine hundred seventy-three thousand, five hundred twenty-five".