166438640880 has 60 divisors (see below), whose sum is σ = 558956438040. Its totient is φ = 44383637376.

The previous prime is 166438640857. The next prime is 166438640887. The reversal of 166438640880 is 88046834661.

166438640880 is a `hidden beast` number, since 166 + 438 + 6 + 40 + 8 + 8 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (60).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166438640887) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 115581670 + ... + 115583109.

It is an arithmetic number, because the mean of its divisors is an integer number (9315940634).

Almost surely, 2^166438640880 is an apocalyptic number.

166438640880 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

166438640880 is an abundant number, since it is smaller than the sum of its proper divisors (392517797160).

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

166438640880 is a wasteful number, since it uses less digits than its factorization.

166438640880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 231164798 (or 231164789 counting only the distinct ones).

The product of its (nonzero) digits is 5308416, while the sum is 54.

The spelling of 166438640880 in words is "one hundred sixty-six billion, four hundred thirty-eight million, six hundred forty thousand, eight hundred eighty".