668514391 has 2 divisors, whose sum is σ = 668514392. Its totient is φ = 668514390.

The previous prime is 668514383. The next prime is 668514439. The reversal of 668514391 is 193415866.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 668514391 - 2³ = 668514383 is a prime.

It is a super-2 number, since 2×668514391² = 893822981948201762, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (668511391) 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, 334257195 + 334257196.

It is an arithmetic number, because the mean of its divisors is an integer number (334257196).

Almost surely, 2^668514391 is an apocalyptic number.

668514391 is a deficient number, since it is larger than the sum of its proper divisors (1).

668514391 is an equidigital number, since it uses as much as digits as its factorization.

668514391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 155520, while the sum is 43.

The square root of 668514391 is about 25855.6452443175. The cubic root of 668514391 is about 874.3867882036.

The spelling of 668514391 in words is "six hundred sixty-eight million, five hundred fourteen thousand, three hundred ninety-one".