166599991296 has 448 divisors, whose sum is σ = 530054271360. Its totient is φ = 52171112448.

The previous prime is 166599991289. The next prime is 166599991319. The reversal of 166599991296 is 692199995661.

166599991296 is a `hidden beast` number, since 1 + 6 + 6 + 599 + 9 + 9 + 1 + 29 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

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, 304570095 + ... + 304570641.

Almost surely, 2^166599991296 is an apocalyptic number.

166599991296 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 166599991296, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (265027135680).

166599991296 is an abundant number, since it is smaller than the sum of its proper divisors (363454280064).

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

166599991296 is an frugal number, since it uses more digits than its factorization.

166599991296 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 611 (or 569 counting only the distinct ones).

The product of its digits is 127545840, while the sum is 72.

The spelling of 166599991296 in words is "one hundred sixty-six billion, five hundred ninety-nine million, nine hundred ninety-one thousand, two hundred ninety-six".