668238028781 has 8 divisors (see below), whose sum is σ = 668825088000. Its totient is φ = 667651073040.

The previous prime is 668238028663. The next prime is 668238028813. The reversal of 668238028781 is 187820832866.

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 668238028781 - 2³⁸ = 393360121837 is a prime.

It is a super-2 number, since 2×668238028781² (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 668238028781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668238024781) 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, 18590216 + ... + 18626126.

It is an arithmetic number, because the mean of its divisors is an integer number (83603136000).

Almost surely, 2^668238028781 is an apocalyptic number.

It is an amenable number.

668238028781 is a deficient number, since it is larger than the sum of its proper divisors (587059219).

668238028781 is a wasteful number, since it uses less digits than its factorization.

668238028781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51739.

The product of its (nonzero) digits is 12386304, while the sum is 59.

The spelling of 668238028781 in words is "six hundred sixty-eight billion, two hundred thirty-eight million, twenty-eight thousand, seven hundred eighty-one".