138172225 has 12 divisors (see below), whose sum is σ = 171539244. Its totient is φ = 110405120.

The previous prime is 138172217. The next prime is 138172231. The reversal of 138172225 is 522271831.

It can be written as a sum of positive squares in 6 ways, for example, as 1656369 + 136515856 = 1287^2 + 11684^2 .

It is not a de Polignac number, because 138172225 - 2³ = 138172217 is a prime.

It is a super-2 number, since 2×138172225² = 38183127522901250, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21597 + ... + 27253.

It is an arithmetic number, because the mean of its divisors is an integer number (14294937).

Almost surely, 2^138172225 is an apocalyptic number.

It is an amenable number.

138172225 is a deficient number, since it is larger than the sum of its proper divisors (33367019).

138172225 is an equidigital number, since it uses as much as digits as its factorization.

138172225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6644 (or 6639 counting only the distinct ones).

The product of its digits is 6720, while the sum is 31.

The square root of 138172225 is about 11754.6682216046. The cubic root of 138172225 is about 516.9798113251.

The spelling of 138172225 in words is "one hundred thirty-eight million, one hundred seventy-two thousand, two hundred twenty-five".