18172388025 has 243 divisors, whose sum is σ = 38657367567. Its totient is φ = 8153006400.

The previous prime is 18172388023. The next prime is 18172388027. The reversal of 18172388025 is 52088327181.

The square root of 18172388025 is 134805.

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

18172388025 is a `hidden beast` number, since 181 + 72 + 388 + 0 + 25 = 666.

It is an interprime number because it is at equal distance from previous prime (18172388023) and next prime (18172388027).

It can be written as a sum of positive squares in only one way, i.e., 6542059689 + 11630328336 = 80883^2 + 107844^2 .

It is not a de Polignac number, because 18172388025 - 2¹ = 18172388023 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (18172388023) by changing a digit.

It is a polite number, since it can be written in 242 ways as a sum of consecutive naturals, for example, 422613654 + ... + 422613696.

Almost surely, 2^18172388025 is an apocalyptic number.

18172388025 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

18172388025 is the 134805-th square number.

18172388025 is the 67403-rd centered octagonal number.

It is an amenable number.

18172388025 is an abundant number, since it is smaller than the sum of its proper divisors (20484979542).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18172388025 is a wasteful number, since it uses less digits than its factorization.

18172388025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 162 (or 81 counting only the distinct ones).

The product of its (nonzero) digits is 215040, while the sum is 45.

The spelling of 18172388025 in words is "eighteen billion, one hundred seventy-two million, three hundred eighty-eight thousand, twenty-five".