668891519 has 2 divisors, whose sum is σ = 668891520. Its totient is φ = 668891518.

The previous prime is 668891453. The next prime is 668891521. The reversal of 668891519 is 915198866.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-668891519 is a prime.

It is a super-2 number, since 2×668891519² = 894831728380254722, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 668891521, 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 (668891539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334445759 + 334445760.

It is an arithmetic number, because the mean of its divisors is an integer number (334445760).

Almost surely, 2^668891519 is an apocalyptic number.

668891519 is a deficient number, since it is larger than the sum of its proper divisors (1).

668891519 is an equidigital number, since it uses as much as digits as its factorization.

668891519 is an evil number, because the sum of its binary digits is even.

The product of its digits is 933120, while the sum is 53.

The square root of 668891519 is about 25862.9371688523. The cubic root of 668891519 is about 874.5511794550.

The spelling of 668891519 in words is "six hundred sixty-eight million, eight hundred ninety-one thousand, five hundred nineteen".