20997525 has 12 divisors (see below), whose sum is σ = 34716032. Its totient is φ = 11198640.

The previous prime is 20997523. The next prime is 20997539. The reversal of 20997525 is 52579902.

It is not a de Polignac number, because 20997525 - 2¹ = 20997523 is a prime.

It is a super-2 number, since 2×20997525² = 881792112251250, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20997521) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 139909 + ... + 140058.

Almost surely, 2^20997525 is an apocalyptic number.

20997525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20997525 is a deficient number, since it is larger than the sum of its proper divisors (13718507).

20997525 is a wasteful number, since it uses less digits than its factorization.

20997525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 279980 (or 279975 counting only the distinct ones).

The product of its (nonzero) digits is 56700, while the sum is 39.

The square root of 20997525 is about 4582.3056423595. The cubic root of 20997525 is about 275.8815785816.

The spelling of 20997525 in words is "twenty million, nine hundred ninety-seven thousand, five hundred twenty-five".