18687861 has 24 divisors (see below), whose sum is σ = 28708160. Its totient is φ = 12014352.

The previous prime is 18687859. The next prime is 18687869. The reversal of 18687861 is 16878681.

It is not a de Polignac number, because 18687861 - 2¹ = 18687859 is a prime.

It is a super-2 number, since 2×18687861² = 698472297510642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18687869) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 22296 + ... + 23118.

Almost surely, 2^18687861 is an apocalyptic number.

It is an amenable number.

18687861 is a deficient number, since it is larger than the sum of its proper divisors (10020299).

18687861 is an equidigital number, since it uses as much as digits as its factorization.

18687861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 890 (or 855 counting only the distinct ones).

The product of its digits is 129024, while the sum is 45.

The square root of 18687861 is about 4322.9458705841. The cubic root of 18687861 is about 265.3708395350.

The spelling of 18687861 in words is "eighteen million, six hundred eighty-seven thousand, eight hundred sixty-one".