166440044689 has 2 divisors, whose sum is σ = 166440044690. Its totient is φ = 166440044688.

The previous prime is 166440044647. The next prime is 166440044809. The reversal of 166440044689 is 986440044661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 149163571089 + 17276473600 = 386217^2 + 131440^2 .

It is a cyclic number.

It is not a de Polignac number, because 166440044689 - 2²¹ = 166437947537 is a prime.

It is not a weakly prime, because it can be changed into another prime (166440044489) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83220022344 + 83220022345.

It is an arithmetic number, because the mean of its divisors is an integer number (83220022345).

Almost surely, 2^166440044689 is an apocalyptic number.

It is an amenable number.

166440044689 is a deficient number, since it is larger than the sum of its proper divisors (1).

166440044689 is an equidigital number, since it uses as much as digits as its factorization.

166440044689 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3981312, while the sum is 52.

The spelling of 166440044689 in words is "one hundred sixty-six billion, four hundred forty million, forty-four thousand, six hundred eighty-nine".