668377391 has 8 divisors (see below), whose sum is σ = 752659968. Its totient is φ = 588015000.

The previous prime is 668377387. The next prime is 668377397. The reversal of 668377391 is 193773866.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 668377391 - 2² = 668377387 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668377397) 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 in 7 ways as a sum of consecutive naturals, for example, 979685 + ... + 980366.

It is an arithmetic number, because the mean of its divisors is an integer number (94082496).

Almost surely, 2^668377391 is an apocalyptic number.

668377391 is a deficient number, since it is larger than the sum of its proper divisors (84282577).

668377391 is a wasteful number, since it uses less digits than its factorization.

668377391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1960093.

The product of its digits is 1143072, while the sum is 50.

The square root of 668377391 is about 25852.9957838545. The cubic root of 668377391 is about 874.3270541747.

The spelling of 668377391 in words is "six hundred sixty-eight million, three hundred seventy-seven thousand, three hundred ninety-one".