668401437643 has 4 divisors (see below), whose sum is σ = 670780090728. Its totient is φ = 666022784560.

The previous prime is 668401437569. The next prime is 668401437653. The reversal of 668401437643 is 346734104866.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-668401437643 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (668401437653) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1189326121 + ... + 1189326682.

It is an arithmetic number, because the mean of its divisors is an integer number (167695022682).

Almost surely, 2^668401437643 is an apocalyptic number.

668401437643 is a deficient number, since it is larger than the sum of its proper divisors (2378653085).

668401437643 is a wasteful number, since it uses less digits than its factorization.

668401437643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2378653084.

The product of its (nonzero) digits is 6967296, while the sum is 52.

The spelling of 668401437643 in words is "six hundred sixty-eight billion, four hundred one million, four hundred thirty-seven thousand, six hundred forty-three".