18387691805 has 16 divisors (see below), whose sum is σ = 25229871360. Its totient is φ = 12602470272.

The previous prime is 18387691799. The next prime is 18387691871. The reversal of 18387691805 is 50819678381.

It is not a de Polignac number, because 18387691805 - 2⁶ = 18387691741 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 57464 + ... + 200193.

It is an arithmetic number, because the mean of its divisors is an integer number (1576866960).

Almost surely, 2^18387691805 is an apocalyptic number.

It is an amenable number.

18387691805 is a deficient number, since it is larger than the sum of its proper divisors (6842179555).

18387691805 is a wasteful number, since it uses less digits than its factorization.

18387691805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 259708.

The product of its (nonzero) digits is 2903040, while the sum is 56.

The spelling of 18387691805 in words is "eighteen billion, three hundred eighty-seven million, six hundred ninety-one thousand, eight hundred five".