18986987133 has 6 divisors (see below), whose sum is σ = 27425648094. Its totient is φ = 12657991416.

The previous prime is 18986987113. The next prime is 18986987141. The reversal of 18986987133 is 33178968981.

It can be written as a sum of positive squares in only one way, i.e., 15389146809 + 3597840324 = 124053^2 + 59982^2 .

It is a de Polignac number, because none of the positive numbers 2^k-18986987133 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18986987113) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1054832610 + ... + 1054832627.

It is an arithmetic number, because the mean of its divisors is an integer number (4570941349).

Almost surely, 2^18986987133 is an apocalyptic number.

It is an amenable number.

18986987133 is a deficient number, since it is larger than the sum of its proper divisors (8438660961).

18986987133 is a wasteful number, since it uses less digits than its factorization.

18986987133 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2109665243 (or 2109665240 counting only the distinct ones).

The product of its digits is 15676416, while the sum is 63.

The spelling of 18986987133 in words is "eighteen billion, nine hundred eighty-six million, nine hundred eighty-seven thousand, one hundred thirty-three".