668915519 has 2 divisors, whose sum is σ = 668915520. Its totient is φ = 668915518.

The previous prime is 668915461. The next prime is 668915521. The reversal of 668915519 is 915519866.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 668915519 - 2¹² = 668911423 is a prime.

It is a super-2 number, since 2×668915519² = 894895943118078722, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 668915521, 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 (668915549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334457759 + 334457760.

It is an arithmetic number, because the mean of its divisors is an integer number (334457760).

Almost surely, 2^668915519 is an apocalyptic number.

668915519 is a deficient number, since it is larger than the sum of its proper divisors (1).

668915519 is an equidigital number, since it uses as much as digits as its factorization.

668915519 is an evil number, because the sum of its binary digits is even.

The product of its digits is 583200, while the sum is 50.

The square root of 668915519 is about 25863.4011491142. The cubic root of 668915519 is about 874.5616390371.

The spelling of 668915519 in words is "six hundred sixty-eight million, nine hundred fifteen thousand, five hundred nineteen".