668619793 has 2 divisors, whose sum is σ = 668619794. Its totient is φ = 668619792.

The previous prime is 668619779. The next prime is 668619827. The reversal of 668619793 is 397916866.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 668584449 + 35344 = 25857^2 + 188^2 .

It is a cyclic number.

It is not a de Polignac number, because 668619793 - 2⁵ = 668619761 is a prime.

It is not a weakly prime, because it can be changed into another prime (668619593) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334309896 + 334309897.

It is an arithmetic number, because the mean of its divisors is an integer number (334309897).

Almost surely, 2^668619793 is an apocalyptic number.

It is an amenable number.

668619793 is a deficient number, since it is larger than the sum of its proper divisors (1).

668619793 is an equidigital number, since it uses as much as digits as its factorization.

668619793 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2939328, while the sum is 55.

The square root of 668619793 is about 25857.6834422575. The cubic root of 668619793 is about 874.4327394822.

The spelling of 668619793 in words is "six hundred sixty-eight million, six hundred nineteen thousand, seven hundred ninety-three".