18151985 has 4 divisors (see below), whose sum is σ = 21782388. Its totient is φ = 14521584.

The previous prime is 18151979. The next prime is 18151993. The reversal of 18151985 is 58915181.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9759376 + 8392609 = 3124^2 + 2897^2 .

It is a cyclic number.

It is not a de Polignac number, because 18151985 - 2⁶ = 18151921 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1815194 + ... + 1815203.

It is an arithmetic number, because the mean of its divisors is an integer number (5445597).

Almost surely, 2^18151985 is an apocalyptic number.

It is an amenable number.

18151985 is a deficient number, since it is larger than the sum of its proper divisors (3630403).

18151985 is an equidigital number, since it uses as much as digits as its factorization.

18151985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3630402.

The product of its digits is 14400, while the sum is 38.

The square root of 18151985 is about 4260.5146402753. The cubic root of 18151985 is about 262.8096904254.

The spelling of 18151985 in words is "eighteen million, one hundred fifty-one thousand, nine hundred eighty-five".