668149919 has 2 divisors, whose sum is σ = 668149920. Its totient is φ = 668149918.

The previous prime is 668149873. The next prime is 668149927. The reversal of 668149919 is 919941866.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 668149919 - 2¹² = 668145823 is a prime.

It is a super-2 number, since 2×668149919² = 892848628519413122, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (668149939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334074959 + 334074960.

It is an arithmetic number, because the mean of its divisors is an integer number (334074960).

Almost surely, 2^668149919 is an apocalyptic number.

668149919 is a deficient number, since it is larger than the sum of its proper divisors (1).

668149919 is an equidigital number, since it uses as much as digits as its factorization.

668149919 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 839808, while the sum is 53.

The square root of 668149919 is about 25848.5960740617. The cubic root of 668149919 is about 874.2278549832.

The spelling of 668149919 in words is "six hundred sixty-eight million, one hundred forty-nine thousand, nine hundred nineteen".