665551673 has 2 divisors, whose sum is σ = 665551674. Its totient is φ = 665551672.

The previous prime is 665551651. The next prime is 665551699. The reversal of 665551673 is 376155566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 652649209 + 12902464 = 25547^2 + 3592^2 .

It is a cyclic number.

It is not a de Polignac number, because 665551673 - 2⁶ = 665551609 is a prime.

It is not a weakly prime, because it can be changed into another prime (665551633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332775836 + 332775837.

It is an arithmetic number, because the mean of its divisors is an integer number (332775837).

Almost surely, 2^665551673 is an apocalyptic number.

It is an amenable number.

665551673 is a deficient number, since it is larger than the sum of its proper divisors (1).

665551673 is an equidigital number, since it uses as much as digits as its factorization.

665551673 is an evil number, because the sum of its binary digits is even.

The product of its digits is 567000, while the sum is 44.

The square root of 665551673 is about 25798.2881796448. The cubic root of 665551673 is about 873.0931746298.

The spelling of 665551673 in words is "six hundred sixty-five million, five hundred fifty-one thousand, six hundred seventy-three".