166620645 has 20 divisors (see below), whose sum is σ = 298683660. Its totient is φ = 88864128.

The previous prime is 166620617. The next prime is 166620653. The reversal of 166620645 is 546026661.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 18122049 + 148498596 = 4257^2 + 12186^2 .

It is not a de Polignac number, because 166620645 - 2¹¹ = 166618597 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

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, 205300 + ... + 206109.

It is an arithmetic number, because the mean of its divisors is an integer number (14934183).

Almost surely, 2^166620645 is an apocalyptic number.

166620645 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

166620645 is a deficient number, since it is larger than the sum of its proper divisors (132063015).

166620645 is an equidigital number, since it uses as much as digits as its factorization.

166620645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 411426 (or 411417 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 166620645 is about 12908.1619528111. The cubic root of 166620645 is about 550.2705500877.

The spelling of 166620645 in words is "one hundred sixty-six million, six hundred twenty thousand, six hundred forty-five".