1664445173 has 2 divisors, whose sum is σ = 1664445174. Its totient is φ = 1664445172.

The previous prime is 1664445157. The next prime is 1664445217. The reversal of 1664445173 is 3715444661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1294344529 + 370100644 = 35977^2 + 19238^2 .

It is a cyclic number.

It is not a de Polignac number, because 1664445173 - 2⁴ = 1664445157 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1664445173.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1664445073) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832222586 + 832222587.

It is an arithmetic number, because the mean of its divisors is an integer number (832222587).

Almost surely, 2^1664445173 is an apocalyptic number.

It is an amenable number.

1664445173 is a deficient number, since it is larger than the sum of its proper divisors (1).

1664445173 is an equidigital number, since it uses as much as digits as its factorization.

1664445173 is an evil number, because the sum of its binary digits is even.

The product of its digits is 241920, while the sum is 41.

The square root of 1664445173 is about 40797.6123443517. The cubic root of 1664445173 is about 1185.1040928814.

The spelling of 1664445173 in words is "one billion, six hundred sixty-four million, four hundred forty-five thousand, one hundred seventy-three".