166506621 has 16 divisors (see below), whose sum is σ = 227667264. Its totient is φ = 108186624.

The previous prime is 166506589. The next prime is 166506631. The reversal of 166506621 is 126605661.

It is not a de Polignac number, because 166506621 - 2⁵ = 166506589 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166506631) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 73315 + ... + 75551.

It is an arithmetic number, because the mean of its divisors is an integer number (14229204).

Almost surely, 2^166506621 is an apocalyptic number.

It is an amenable number.

166506621 is a deficient number, since it is larger than the sum of its proper divisors (61160643).

166506621 is a wasteful number, since it uses less digits than its factorization.

166506621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2860.

The product of its (nonzero) digits is 12960, while the sum is 33.

The square root of 166506621 is about 12903.7444565521. The cubic root of 166506621 is about 550.1449986847.

The spelling of 166506621 in words is "one hundred sixty-six million, five hundred six thousand, six hundred twenty-one".