665022661 has 2 divisors, whose sum is σ = 665022662. Its totient is φ = 665022660.

The previous prime is 665022647. The next prime is 665022691. The reversal of 665022661 is 166220566.

665022661 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 611820225 + 53202436 = 24735^2 + 7294^2 .

It is a cyclic number.

It is not a de Polignac number, because 665022661 - 2¹¹ = 665020613 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665022691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332511330 + 332511331.

It is an arithmetic number, because the mean of its divisors is an integer number (332511331).

Almost surely, 2^665022661 is an apocalyptic number.

It is an amenable number.

665022661 is a deficient number, since it is larger than the sum of its proper divisors (1).

665022661 is an equidigital number, since it uses as much as digits as its factorization.

665022661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 34.

The square root of 665022661 is about 25788.0332906563. The cubic root of 665022661 is about 872.8617880407.

The spelling of 665022661 in words is "six hundred sixty-five million, twenty-two thousand, six hundred sixty-one".