18691853868 has 240 divisors, whose sum is σ = 52206206976. Its totient is φ = 5822046720.

The previous prime is 18691853863. The next prime is 18691853927. The reversal of 18691853868 is 86835819681.

18691853868 is a `hidden beast` number, since 1 + 8 + 6 + 91 + 8 + 538 + 6 + 8 = 666.

It is a super-2 number, since 2×18691853868² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18691853863) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 48803605 + ... + 48803987.

Almost surely, 2^18691853868 is an apocalyptic number.

18691853868 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18691853868, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26103103488).

18691853868 is an abundant number, since it is smaller than the sum of its proper divisors (33514353108).

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

18691853868 is a wasteful number, since it uses less digits than its factorization.

18691853868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 586 (or 575 counting only the distinct ones).

The product of its digits is 19906560, while the sum is 63.

The spelling of 18691853868 in words is "eighteen billion, six hundred ninety-one million, eight hundred fifty-three thousand, eight hundred sixty-eight".