18407587991 has 24 divisors (see below), whose sum is σ = 20714428800. Its totient is φ = 16332451200.

The previous prime is 18407587969. The next prime is 18407588063. The reversal of 18407587991 is 19978570481.

It is a de Polignac number, because none of the positive numbers 2^k-18407587991 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18407587991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18407587291) 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, 768821 + ... + 792401.

It is an arithmetic number, because the mean of its divisors is an integer number (863101200).

Almost surely, 2^18407587991 is an apocalyptic number.

18407587991 is a deficient number, since it is larger than the sum of its proper divisors (2306840809).

18407587991 is a wasteful number, since it uses less digits than its factorization.

18407587991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23787 (or 23774 counting only the distinct ones).

The product of its (nonzero) digits is 5080320, while the sum is 59.

The spelling of 18407587991 in words is "eighteen billion, four hundred seven million, five hundred eighty-seven thousand, nine hundred ninety-one".