18171994 has 8 divisors (see below), whose sum is σ = 27283860. Its totient is φ = 9077376.

The previous prime is 18171991. The next prime is 18172019. The reversal of 18171994 is 49917181.

It can be written as a sum of positive squares in 2 ways, for example, as 17766225 + 405769 = 4215^2 + 637^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (18171991) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1239 + ... + 6154.

Almost surely, 2^18171994 is an apocalyptic number.

18171994 is a deficient number, since it is larger than the sum of its proper divisors (9111866).

18171994 is a wasteful number, since it uses less digits than its factorization.

18171994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8624.

The product of its digits is 18144, while the sum is 40.

The square root of 18171994 is about 4262.8621840261. The cubic root of 18171994 is about 262.9062203293.

The spelling of 18171994 in words is "eighteen million, one hundred seventy-one thousand, nine hundred ninety-four".