668822417 has 2 divisors, whose sum is σ = 668822418. Its totient is φ = 668822416.

The previous prime is 668822377. The next prime is 668822419. The reversal of 668822417 is 714228866.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 446096641 + 222725776 = 21121^2 + 14924^2 .

It is a cyclic number.

It is not a de Polignac number, because 668822417 - 2¹⁸ = 668560273 is a prime.

Together with 668822419, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (668822419) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334411208 + 334411209.

It is an arithmetic number, because the mean of its divisors is an integer number (334411209).

Almost surely, 2^668822417 is an apocalyptic number.

It is an amenable number.

668822417 is a deficient number, since it is larger than the sum of its proper divisors (1).

668822417 is an equidigital number, since it uses as much as digits as its factorization.

668822417 is an evil number, because the sum of its binary digits is even.

The product of its digits is 258048, while the sum is 44.

The square root of 668822417 is about 25861.6012071952. The cubic root of 668822417 is about 874.5210623059.

The spelling of 668822417 in words is "six hundred sixty-eight million, eight hundred twenty-two thousand, four hundred seventeen".