166561133 has 2 divisors, whose sum is σ = 166561134. Its totient is φ = 166561132.

The previous prime is 166561127. The next prime is 166561141. The reversal of 166561133 is 331165661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 118091689 + 48469444 = 10867^2 + 6962^2 .

It is a cyclic number.

It is not a de Polignac number, because 166561133 - 2⁴ = 166561117 is a prime.

It is a super-2 number, since 2×166561133² = 55485222052487378, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 166561133.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166561103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83280566 + 83280567.

It is an arithmetic number, because the mean of its divisors is an integer number (83280567).

Almost surely, 2^166561133 is an apocalyptic number.

It is an amenable number.

166561133 is a deficient number, since it is larger than the sum of its proper divisors (1).

166561133 is an equidigital number, since it uses as much as digits as its factorization.

166561133 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9720, while the sum is 32.

The square root of 166561133 is about 12905.8565387966. The cubic root of 166561133 is about 550.2050287941.

The spelling of 166561133 in words is "one hundred sixty-six million, five hundred sixty-one thousand, one hundred thirty-three".