16638925 has 6 divisors (see below), whose sum is σ = 20632298. Its totient is φ = 13311120.

The previous prime is 16638917. The next prime is 16638931. The reversal of 16638925 is 52983661.

It can be written as a sum of positive squares in 3 ways, for example, as 1225449 + 15413476 = 1107^2 + 3926^2 .

It is not a de Polignac number, because 16638925 - 2³ = 16638917 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 (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 332754 + ... + 332803.

Almost surely, 2^16638925 is an apocalyptic number.

It is an amenable number.

16638925 is a deficient number, since it is larger than the sum of its proper divisors (3993373).

16638925 is an equidigital number, since it uses as much as digits as its factorization.

16638925 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 665567 (or 665562 counting only the distinct ones).

The product of its digits is 77760, while the sum is 40.

The square root of 16638925 is about 4079.0838432177. The cubic root of 16638925 is about 255.2946740859.

The spelling of 16638925 in words is "sixteen million, six hundred thirty-eight thousand, nine hundred twenty-five".