668472661 has 2 divisors, whose sum is σ = 668472662. Its totient is φ = 668472660.

The previous prime is 668472659. The next prime is 668472683. The reversal of 668472661 is 166274866.

668472661 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., 667240561 + 1232100 = 25831^2 + 1110^2 .

It is a cyclic number.

It is not a de Polignac number, because 668472661 - 2¹ = 668472659 is a prime.

Together with 668472659, 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 (668472061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334236330 + 334236331.

It is an arithmetic number, because the mean of its divisors is an integer number (334236331).

Almost surely, 2^668472661 is an apocalyptic number.

It is an amenable number.

668472661 is a deficient number, since it is larger than the sum of its proper divisors (1).

668472661 is an equidigital number, since it uses as much as digits as its factorization.

668472661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 580608, while the sum is 46.

The square root of 668472661 is about 25854.8382512829. The cubic root of 668472661 is about 874.3685941700.

The spelling of 668472661 in words is "six hundred sixty-eight million, four hundred seventy-two thousand, six hundred sixty-one".