18361815516 has 72 divisors (see below), whose sum is σ = 51389904384. Its totient is φ = 5481131040.

The previous prime is 18361815463. The next prime is 18361815643. The reversal of 18361815516 is 61551816381.

It is a happy number.

18361815516 is a `hidden beast` number, since 1 + 8 + 3 + 618 + 15 + 5 + 16 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 319500 + ... + 372563.

It is an arithmetic number, because the mean of its divisors is an integer number (713748672).

Almost surely, 2^18361815516 is an apocalyptic number.

It is an amenable number.

18361815516 is an abundant number, since it is smaller than the sum of its proper divisors (33028088868).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18361815516 is a wasteful number, since it uses less digits than its factorization.

18361815516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 692151 (or 692146 counting only the distinct ones).

The product of its digits is 172800, while the sum is 45.

The spelling of 18361815516 in words is "eighteen billion, three hundred sixty-one million, eight hundred fifteen thousand, five hundred sixteen".