17991012816 has 160 divisors (see below), whose sum is σ = 60132222720. Its totient is φ = 5043257856.

The previous prime is 17991012811. The next prime is 17991012901. The reversal of 17991012816 is 61821019971.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (17991012811) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 104146 + ... + 216398.

It is an arithmetic number, because the mean of its divisors is an integer number (375826392).

Almost surely, 2^17991012816 is an apocalyptic number.

17991012816 is a gapful number since it is divisible by the number (16) 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 17991012816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30066111360).

17991012816 is an abundant number, since it is smaller than the sum of its proper divisors (42141209904).

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

17991012816 is a wasteful number, since it uses less digits than its factorization.

17991012816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112330 (or 112318 counting only the distinct ones).

The product of its (nonzero) digits is 54432, while the sum is 45.

The spelling of 17991012816 in words is "seventeen billion, nine hundred ninety-one million, twelve thousand, eight hundred sixteen".