18987394 has 8 divisors (see below), whose sum is σ = 28763388. Its totient is φ = 9399600.

The previous prime is 18987391. The next prime is 18987457. The reversal of 18987394 is 49378981.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 12510369 + 6477025 = 3537^2 + 2545^2 .

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

It is a super-2 number, since 2×18987394² = 721042261822472, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18987391) 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, 46797 + ... + 47200.

Almost surely, 2^18987394 is an apocalyptic number.

18987394 is a deficient number, since it is larger than the sum of its proper divisors (9775994).

18987394 is a wasteful number, since it uses less digits than its factorization.

18987394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94100.

The product of its digits is 435456, while the sum is 49.

The square root of 18987394 is about 4357.4526962435. The cubic root of 18987394 is about 266.7811380069.

The spelling of 18987394 in words is "eighteen million, nine hundred eighty-seven thousand, three hundred ninety-four".