18915876225 has 81 divisors (see below), whose sum is σ = 34732510267. Its totient is φ = 9840904320.

The previous prime is 18915876173. The next prime is 18915876229. The reversal of 18915876225 is 52267851981.

The square root of 18915876225 is 137535.

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

18915876225 is a `hidden beast` number, since 1 + 8 + 9 + 1 + 5 + 8 + 7 + 622 + 5 = 666.

It can be written as a sum of positive squares in 13 ways, for example, as 887980401 + 18027895824 = 29799^2 + 134268^2 .

It is not a de Polignac number, because 18915876225 - 2⁷ = 18915876097 is a prime.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18915876229) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 109340239 + ... + 109340411.

Almost surely, 2^18915876225 is an apocalyptic number.

18915876225 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

18915876225 is the 137535-th square number.

18915876225 is the 68768-th centered octagonal number.

It is an amenable number.

18915876225 is a deficient number, since it is larger than the sum of its proper divisors (15816634042).

18915876225 is an equidigital number, since it uses as much as digits as its factorization.

18915876225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 468 (or 234 counting only the distinct ones).

The product of its digits is 2419200, while the sum is 54.

The spelling of 18915876225 in words is "eighteen billion, nine hundred fifteen million, eight hundred seventy-six thousand, two hundred twenty-five".