18721506087 has 24 divisors (see below), whose sum is σ = 27904775600. Its totient is φ = 12086081280.

The previous prime is 18721506077. The next prime is 18721506101. The reversal of 18721506087 is 78060512781.

It is a happy number.

18721506087 is a `hidden beast` number, since 18 + 7 + 21 + 5 + 0 + 608 + 7 = 666.

It is not a de Polignac number, because 18721506087 - 2²⁴ = 18704728871 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18721506007) 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, 62962 + ... + 203487.

Almost surely, 2^18721506087 is an apocalyptic number.

18721506087 is a deficient number, since it is larger than the sum of its proper divisors (9183269513).

18721506087 is a wasteful number, since it uses less digits than its factorization.

18721506087 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 266703 (or 266700 counting only the distinct ones).

The product of its (nonzero) digits is 188160, while the sum is 45.

The spelling of 18721506087 in words is "eighteen billion, seven hundred twenty-one million, five hundred six thousand, eighty-seven".