166215666 has 16 divisors (see below), whose sum is σ = 334634688. Its totient is φ = 55038000.

The previous prime is 166215659. The next prime is 166215689. The reversal of 166215666 is 666512661.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 90825 + ... + 92636.

It is an arithmetic number, because the mean of its divisors is an integer number (20914668).

Almost surely, 2^166215666 is an apocalyptic number.

166215666 is an abundant number, since it is smaller than the sum of its proper divisors (168419022).

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

166215666 is a wasteful number, since it uses less digits than its factorization.

166215666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 183617.

The product of its digits is 77760, while the sum is 39.

The square root of 166215666 is about 12892.4654740666. The cubic root of 166215666 is about 549.8243692664.

The spelling of 166215666 in words is "one hundred sixty-six million, two hundred fifteen thousand, six hundred sixty-six".