166657641 has 4 divisors (see below), whose sum is σ = 222210192. Its totient is φ = 111105092.

The previous prime is 166657633. The next prime is 166657649. The reversal of 166657641 is 146756661.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 146756661 = 3 ⋅48918887.

It is an interprime number because it is at equal distance from previous prime (166657633) and next prime (166657649).

It is a cyclic number.

It is not a de Polignac number, because 166657641 - 2³ = 166657633 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 166657593 and 166657602.

It is not an unprimeable number, because it can be changed into a prime (166657649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27776271 + ... + 27776276.

It is an arithmetic number, because the mean of its divisors is an integer number (55552548).

Almost surely, 2^166657641 is an apocalyptic number.

It is an amenable number.

166657641 is a deficient number, since it is larger than the sum of its proper divisors (55552551).

166657641 is an equidigital number, since it uses as much as digits as its factorization.

166657641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55552550.

The product of its digits is 181440, while the sum is 42.

The square root of 166657641 is about 12909.5949200585. The cubic root of 166657641 is about 550.3112739382.

The spelling of 166657641 in words is "one hundred sixty-six million, six hundred fifty-seven thousand, six hundred forty-one".