668921890591 has 8 divisors (see below), whose sum is σ = 697392899280. Its totient is φ = 641037913152.

The previous prime is 668921890579. The next prime is 668921890631. The reversal of 668921890591 is 195098129866.

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 668921890591 - 2³³ = 660331955999 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 (668921860591) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 146755486 + ... + 146760043.

It is an arithmetic number, because the mean of its divisors is an integer number (87174112410).

Almost surely, 2^668921890591 is an apocalyptic number.

668921890591 is a deficient number, since it is larger than the sum of its proper divisors (28471008689).

668921890591 is a wasteful number, since it uses less digits than its factorization.

668921890591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 293515625.

The product of its (nonzero) digits is 16796160, while the sum is 64.

The spelling of 668921890591 in words is "six hundred sixty-eight billion, nine hundred twenty-one million, eight hundred ninety thousand, five hundred ninety-one".