673651661 has 2 divisors, whose sum is σ = 673651662. Its totient is φ = 673651660.

The previous prime is 673651651. The next prime is 673651663. The reversal of 673651661 is 166156376.

673651661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 515017636 + 158634025 = 22694^2 + 12595^2 .

It is a cyclic number.

It is not a de Polignac number, because 673651661 - 2⁶ = 673651597 is a prime.

Together with 673651663, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (673651663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 336825830 + 336825831.

It is an arithmetic number, because the mean of its divisors is an integer number (336825831).

Almost surely, 2^673651661 is an apocalyptic number.

It is an amenable number.

673651661 is a deficient number, since it is larger than the sum of its proper divisors (1).

673651661 is an equidigital number, since it uses as much as digits as its factorization.

673651661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 136080, while the sum is 41.

The square root of 673651661 is about 25954.8003459861. The cubic root of 673651661 is about 876.6208480988.

The spelling of 673651661 in words is "six hundred seventy-three million, six hundred fifty-one thousand, six hundred sixty-one".