166153661 has 4 divisors (see below), whose sum is σ = 166311324. Its totient is φ = 165996000.

The previous prime is 166153649. The next prime is 166153667. The reversal of 166153661 is 166351661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 166351661 = 7 ⋅23764523.

It can be written as a sum of positive squares in 2 ways, for example, as 144120025 + 22033636 = 12005^2 + 4694^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166153661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166153667) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 77240 + ... + 79361.

It is an arithmetic number, because the mean of its divisors is an integer number (41577831).

Almost surely, 2^166153661 is an apocalyptic number.

It is an amenable number.

166153661 is a deficient number, since it is larger than the sum of its proper divisors (157663).

166153661 is a wasteful number, since it uses less digits than its factorization.

166153661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157662.

The product of its digits is 19440, while the sum is 35.

The square root of 166153661 is about 12890.0605506724. The cubic root of 166153661 is about 549.7559920372.

The spelling of 166153661 in words is "one hundred sixty-six million, one hundred fifty-three thousand, six hundred sixty-one".