668008557581 has 8 divisors (see below), whose sum is σ = 674797066944. Its totient is φ = 661253244480.

The previous prime is 668008557577. The next prime is 668008557599. The reversal of 668008557581 is 185755800866.

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 668008557581 - 2² = 668008557577 is a prime.

It is a super-2 number, since 2×668008557581² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 668008557581.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668008557511) 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, 8258615 + ... + 8339108.

It is an arithmetic number, because the mean of its divisors is an integer number (84349633368).

Almost surely, 2^668008557581 is an apocalyptic number.

It is an amenable number.

668008557581 is a deficient number, since it is larger than the sum of its proper divisors (6788509363).

668008557581 is a wasteful number, since it uses less digits than its factorization.

668008557581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16598131.

The product of its (nonzero) digits is 16128000, while the sum is 59.

The spelling of 668008557581 in words is "six hundred sixty-eight billion, eight million, five hundred fifty-seven thousand, five hundred eighty-one".