18806690538 has 64 divisors (see below), whose sum is σ = 44278773120. Its totient is φ = 5896440576.

The previous prime is 18806690509. The next prime is 18806690563. The reversal of 18806690538 is 83509660881.

18806690538 is a `hidden beast` number, since 18 + 8 + 0 + 6 + 6 + 90 + 538 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1708420 + ... + 1719392.

It is an arithmetic number, because the mean of its divisors is an integer number (691855830).

Almost surely, 2^18806690538 is an apocalyptic number.

18806690538 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 18806690538, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22139386560).

18806690538 is an abundant number, since it is smaller than the sum of its proper divisors (25472082582).

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

18806690538 is a wasteful number, since it uses less digits than its factorization.

18806690538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12868 (or 12862 counting only the distinct ones).

The product of its (nonzero) digits is 2488320, while the sum is 54.

The spelling of 18806690538 in words is "eighteen billion, eight hundred six million, six hundred ninety thousand, five hundred thirty-eight".