1638225625 has 15 divisors (see below), whose sum is σ = 2048391961. Its totient is φ = 1309771000.

The previous prime is 1638225599. The next prime is 1638225629. The reversal of 1638225625 is 5265228361.

It is a happy number.

The square root of 1638225625 is 40475.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 2 ways, for example, as 128436889 + 1509788736 = 11333^2 + 38856^2 .

It is not a de Polignac number, because 1638225625 - 2⁵ = 1638225593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1638225629) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 1011066 + ... + 1012684.

Almost surely, 2^1638225625 is an apocalyptic number.

1638225625 is the 40475-th square number.

1638225625 is the 20238-th centered octagonal number.

It is an amenable number.

1638225625 is a deficient number, since it is larger than the sum of its proper divisors (410166336).

1638225625 is an frugal number, since it uses more digits than its factorization.

1638225625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3258 (or 1624 counting only the distinct ones).

The product of its digits is 172800, while the sum is 40.

The cubic root of 1638225625 is about 1178.8482549696.

The spelling of 1638225625 in words is "one billion, six hundred thirty-eight million, two hundred twenty-five thousand, six hundred twenty-five".