18891128025 has 405 divisors, whose sum is σ = 46090155293. Its totient is φ = 7389043200.

The previous prime is 18891127987. The next prime is 18891128041. The reversal of 18891128025 is 52082119881.

The square root of 18891128025 is 137445.

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

It can be written as a sum of positive squares in 4 ways, for example, as 441882441 + 18449245584 = 21021^2 + 135828^2 .

It is not a de Polignac number, because 18891128025 - 2²¹ = 18889030873 is a prime.

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

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 404 ways as a sum of consecutive naturals, for example, 1111242817 + ... + 1111242833.

Almost surely, 2^18891128025 is an apocalyptic number.

18891128025 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

18891128025 is the 137445-th square number.

18891128025 is the 68723-rd centered octagonal number.

It is an amenable number.

18891128025 is an abundant number, since it is smaller than the sum of its proper divisors (27199027268).

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

18891128025 is a wasteful number, since it uses less digits than its factorization.

18891128025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100 (or 43 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 45.

The spelling of 18891128025 in words is "eighteen billion, eight hundred ninety-one million, one hundred twenty-eight thousand, twenty-five".