20506725 has 18 divisors (see below), whose sum is σ = 36730226. Its totient is φ = 10936800.

The previous prime is 20506723. The next prime is 20506729. The reversal of 20506725 is 52760502.

It can be written as a sum of positive squares in 3 ways, for example, as 12996 + 20493729 = 114^2 + 4527^2 .

It is not a de Polignac number, because 20506725 - 2¹ = 20506723 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20506723) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 45346 + ... + 45795.

Almost surely, 2^20506725 is an apocalyptic number.

20506725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20506725 is a deficient number, since it is larger than the sum of its proper divisors (16223501).

20506725 is a wasteful number, since it uses less digits than its factorization.

20506725 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91157 (or 91149 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 27.

The square root of 20506725 is about 4528.4351601850. The cubic root of 20506725 is about 273.7151078316.

The spelling of 20506725 in words is "twenty million, five hundred six thousand, seven hundred twenty-five".