18515225 has 12 divisors (see below), whose sum is σ = 23238096. Its totient is φ = 14632080.

The previous prime is 18515221. The next prime is 18515243. The reversal of 18515225 is 52251581.

It is not a de Polignac number, because 18515225 - 2² = 18515221 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18515221) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2387 + ... + 6536.

It is an arithmetic number, because the mean of its divisors is an integer number (1936508).

Almost surely, 2^18515225 is an apocalyptic number.

It is an amenable number.

18515225 is a deficient number, since it is larger than the sum of its proper divisors (4722871).

18515225 is an equidigital number, since it uses as much as digits as its factorization.

18515225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9016 (or 9011 counting only the distinct ones).

The product of its digits is 4000, while the sum is 29.

The square root of 18515225 is about 4302.9321398321. The cubic root of 18515225 is about 264.5511566605.

The spelling of 18515225 in words is "eighteen million, five hundred fifteen thousand, two hundred twenty-five".