20661925 has 6 divisors (see below), whose sum is σ = 25620818. Its totient is φ = 16529520.

The previous prime is 20661917. The next prime is 20661941. The reversal of 20661925 is 52916602.

It can be written as a sum of positive squares in 3 ways, for example, as 7134241 + 13527684 = 2671^2 + 3678^2 .

It is not a de Polignac number, because 20661925 - 2³ = 20661917 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 413214 + ... + 413263.

Almost surely, 2^20661925 is an apocalyptic number.

20661925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20661925 is a deficient number, since it is larger than the sum of its proper divisors (4958893).

20661925 is an equidigital number, since it uses as much as digits as its factorization.

20661925 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 826487 (or 826482 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 20661925 is about 4545.5390219423. The cubic root of 20661925 is about 274.4038878162.

The spelling of 20661925 in words is "twenty million, six hundred sixty-one thousand, nine hundred twenty-five".