18987874 has 4 divisors (see below), whose sum is σ = 28481814. Its totient is φ = 9493936.

The previous prime is 18987863. The next prime is 18987877. The reversal of 18987874 is 47878981.

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

It can be written as a sum of positive squares in only one way, i.e., 14386849 + 4601025 = 3793^2 + 2145^2 .

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (18987877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4746967 + ... + 4746970.

Almost surely, 2^18987874 is an apocalyptic number.

18987874 is a deficient number, since it is larger than the sum of its proper divisors (9493940).

18987874 is an equidigital number, since it uses as much as digits as its factorization.

18987874 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9493939.

The product of its digits is 903168, while the sum is 52.

The square root of 18987874 is about 4357.5077739460. The cubic root of 18987874 is about 266.7833860575.

The spelling of 18987874 in words is "eighteen million, nine hundred eighty-seven thousand, eight hundred seventy-four".