18987859 has 16 divisors (see below), whose sum is σ = 22279680. Its totient is φ = 15996960.

The previous prime is 18987853. The next prime is 18987863. The reversal of 18987859 is 95878981.

It is a cyclic number.

It is not a de Polignac number, because 18987859 - 2⁹ = 18987347 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18987853) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8857 + ... + 10789.

It is an arithmetic number, because the mean of its divisors is an integer number (1392480).

Almost surely, 2^18987859 is an apocalyptic number.

18987859 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

18987859 is a deficient number, since it is larger than the sum of its proper divisors (3291821).

18987859 is a wasteful number, since it uses less digits than its factorization.

18987859 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2010.

The product of its digits is 1451520, while the sum is 55.

The square root of 18987859 is about 4357.5060527784. The cubic root of 18987859 is about 266.7833158065.

The spelling of 18987859 in words is "eighteen million, nine hundred eighty-seven thousand, eight hundred fifty-nine".