20731525 has 12 divisors (see below), whose sum is σ = 25899012. Its totient is φ = 16461440.

The previous prime is 20731499. The next prime is 20731553. The reversal of 20731525 is 52513702.

It can be written as a sum of positive squares in 6 ways, for example, as 2490084 + 18241441 = 1578^2 + 4271^2 .

It is not a de Polignac number, because 20731525 - 2⁷ = 20731397 is a prime.

It is a super-2 number, since 2×20731525² = 859592257651250, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20731525.

It is a congruent 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, 399 + ... + 6451.

It is an arithmetic number, because the mean of its divisors is an integer number (2158251).

Almost surely, 2^20731525 is an apocalyptic number.

20731525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20731525 is a deficient number, since it is larger than the sum of its proper divisors (5167487).

20731525 is a wasteful number, since it uses less digits than its factorization.

20731525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6200 (or 6195 counting only the distinct ones).

The product of its (nonzero) digits is 2100, while the sum is 25.

The square root of 20731525 is about 4553.1884432780. The cubic root of 20731525 is about 274.7116536882.

The spelling of 20731525 in words is "twenty million, seven hundred thirty-one thousand, five hundred twenty-five".