18039987 has 36 divisors (see below), whose sum is σ = 31922280. Its totient is φ = 9761472.

The previous prime is 18039961. The next prime is 18039997. The reversal of 18039987 is 78993081.

18039987 is a `hidden beast` number, since 180 + 399 + 87 = 666.

It is not a de Polignac number, because 18039987 - 2⁸ = 18039731 is a prime.

It is a super-2 number, since 2×18039987² = 650882261920338, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18039997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 7303 + ... + 9455.

It is an arithmetic number, because the mean of its divisors is an integer number (886730).

Almost surely, 2^18039987 is an apocalyptic number.

18039987 is a deficient number, since it is larger than the sum of its proper divisors (13882293).

18039987 is a wasteful number, since it uses less digits than its factorization.

18039987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2192 (or 2182 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 45.

The square root of 18039987 is about 4247.3505859536. The cubic root of 18039987 is about 262.2680617924.

The spelling of 18039987 in words is "eighteen million, thirty-nine thousand, nine hundred eighty-seven".