20508725 has 6 divisors (see below), whose sum is σ = 25430850. Its totient is φ = 16406960.

The previous prime is 20508707. The next prime is 20508731. The reversal of 20508725 is 52780502.

It can be written as a sum of positive squares in 3 ways, for example, as 357604 + 20151121 = 598^2 + 4489^2 .

It is not a de Polignac number, because 20508725 - 2⁶ = 20508661 is a prime.

It is a super-2 number, since 2×20508725² = 841215602251250, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 410150 + ... + 410199.

It is an arithmetic number, because the mean of its divisors is an integer number (4238475).

Almost surely, 2^20508725 is an apocalyptic number.

20508725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20508725 is a deficient number, since it is larger than the sum of its proper divisors (4922125).

20508725 is an equidigital number, since it uses as much as digits as its factorization.

20508725 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 820359 (or 820354 counting only the distinct ones).

The product of its (nonzero) digits is 5600, while the sum is 29.

The square root of 20508725 is about 4528.6559816352. The cubic root of 20508725 is about 273.7240059275.

The spelling of 20508725 in words is "twenty million, five hundred eight thousand, seven hundred twenty-five".