166666820 has 24 divisors (see below), whose sum is σ = 354932928. Its totient is φ = 65727200.

The previous prime is 166666783. The next prime is 166666831. The reversal of 166666820 is 28666661.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 57266 + ... + 60105.

It is an arithmetic number, because the mean of its divisors is an integer number (14788872).

Almost surely, 2^166666820 is an apocalyptic number.

166666820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

166666820 is an abundant number, since it is smaller than the sum of its proper divisors (188266108).

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

166666820 is a wasteful number, since it uses less digits than its factorization.

166666820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117451 (or 117449 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 41.

The square root of 166666820 is about 12909.9504259312. The cubic root of 166666820 is about 550.3213769142.

It can be divided in two parts, 1666 and 66820, that added together give a palindrome (68486).

The spelling of 166666820 in words is "one hundred sixty-six million, six hundred sixty-six thousand, eight hundred twenty".