166635021 has 16 divisors (see below), whose sum is σ = 258712704. Its totient is φ = 93422784.

The previous prime is 166634953. The next prime is 166635047. The reversal of 166635021 is 120536661.

It is not a de Polignac number, because 166635021 - 2⁹ = 166634509 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 166635021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166635061) 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, 73746 + ... + 75971.

It is an arithmetic number, because the mean of its divisors is an integer number (16169544).

Almost surely, 2^166635021 is an apocalyptic number.

It is an amenable number.

166635021 is a deficient number, since it is larger than the sum of its proper divisors (92077683).

166635021 is a wasteful number, since it uses less digits than its factorization.

166635021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149780.

The product of its (nonzero) digits is 6480, while the sum is 30.

The square root of 166635021 is about 12908.7187977739. The cubic root of 166635021 is about 550.2863753814.

The spelling of 166635021 in words is "one hundred sixty-six million, six hundred thirty-five thousand, twenty-one".