20513725 has 24 divisors (see below), whose sum is σ = 26594528. Its totient is φ = 15681600.

The previous prime is 20513687. The next prime is 20513729. The reversal of 20513725 is 52731502.

It is a de Polignac number, because none of the positive numbers 2^k-20513725 is a prime.

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 20513725.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20513729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 61810 + ... + 62140.

Almost surely, 2^20513725 is an apocalyptic number.

20513725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20513725 is a deficient number, since it is larger than the sum of its proper divisors (6080803).

20513725 is a wasteful number, since it uses less digits than its factorization.

20513725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 445 (or 440 counting only the distinct ones).

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

The square root of 20513725 is about 4529.2079881586. The cubic root of 20513725 is about 273.7462486368.

It can be divided in two parts, 2051 and 3725, that added together give a square (5776 = 76²).

The spelling of 20513725 in words is "twenty million, five hundred thirteen thousand, seven hundred twenty-five".