18786987 has 6 divisors (see below), whose sum is σ = 27136772. Its totient is φ = 12524652.

The previous prime is 18786973. The next prime is 18786997. The reversal of 18786987 is 78968781.

It is not a de Polignac number, because 18786987 - 2⁶ = 18786923 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18786907) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1043713 + ... + 1043730.

Almost surely, 2^18786987 is an apocalyptic number.

18786987 is a deficient number, since it is larger than the sum of its proper divisors (8349785).

18786987 is a wasteful number, since it uses less digits than its factorization.

18786987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2087449 (or 2087446 counting only the distinct ones).

The product of its digits is 1354752, while the sum is 54.

The square root of 18786987 is about 4334.3958056458. The cubic root of 18786987 is about 265.8392144566.

The spelling of 18786987 in words is "eighteen million, seven hundred eighty-six thousand, nine hundred eighty-seven".