18698987 has 4 divisors (see below), whose sum is σ = 18924360. Its totient is φ = 18473616.

The previous prime is 18698971. The next prime is 18699013. The reversal of 18698987 is 78989681.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78989681 = 2239 ⋅35279.

It is a cyclic number.

It is not a de Polignac number, because 18698987 - 2⁴ = 18698971 is a prime.

It is a super-2 number, since 2×18698987² = 699304229652338, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18698957) 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, 112562 + ... + 112727.

It is an arithmetic number, because the mean of its divisors is an integer number (4731090).

Almost surely, 2^18698987 is an apocalyptic number.

18698987 is a deficient number, since it is larger than the sum of its proper divisors (225373).

18698987 is an equidigital number, since it uses as much as digits as its factorization.

18698987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 225372.

The product of its digits is 1741824, while the sum is 56.

The square root of 18698987 is about 4324.2325330629. The cubic root of 18698987 is about 265.4234927916.

It can be divided in two parts, 1869898 and 7, that multiplied together give a triangular number (13089286 = T₅₁₁₆).

The spelling of 18698987 in words is "eighteen million, six hundred ninety-eight thousand, nine hundred eighty-seven".