18687645 has 16 divisors (see below), whose sum is σ = 33222720. Its totient is φ = 9966672.

The previous prime is 18687587. The next prime is 18687731. The reversal of 18687645 is 54678681.

It is a happy number.

It is not a de Polignac number, because 18687645 - 2⁷ = 18687517 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 18687645.

It is a congruent number.

It is an unprimeable number.

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, 69079 + ... + 69348.

It is an arithmetic number, because the mean of its divisors is an integer number (2076420).

Almost surely, 2^18687645 is an apocalyptic number.

18687645 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

18687645 is a deficient number, since it is larger than the sum of its proper divisors (14535075).

18687645 is a wasteful number, since it uses less digits than its factorization.

18687645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138441 (or 138435 counting only the distinct ones).

The product of its digits is 322560, while the sum is 45.

The square root of 18687645 is about 4322.9208875481. The cubic root of 18687645 is about 265.3698171187.

The spelling of 18687645 in words is "eighteen million, six hundred eighty-seven thousand, six hundred forty-five".