642166218 has 40 divisors (see below), whose sum is σ = 1514668320. Its totient is φ = 202788360.

The previous prime is 642166201. The next prime is 642166243. The reversal of 642166218 is 812661246.

642166218 is a `hidden beast` number, since 6 + 4 + 21 + 6 + 621 + 8 = 666.

642166218 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 101238 + ... + 107393.

It is an arithmetic number, because the mean of its divisors is an integer number (37866708).

Almost surely, 2^642166218 is an apocalyptic number.

642166218 is an abundant number, since it is smaller than the sum of its proper divisors (872502102).

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

642166218 is a wasteful number, since it uses less digits than its factorization.

642166218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 208664 (or 208655 counting only the distinct ones).

The product of its digits is 27648, while the sum is 36.

The square root of 642166218 is about 25340.9987569551. The cubic root of 642166218 is about 862.7450676009.

The spelling of 642166218 in words is "six hundred forty-two million, one hundred sixty-six thousand, two hundred eighteen".