668782013 has 4 divisors (see below), whose sum is σ = 671951808. Its totient is φ = 665612220.

The previous prime is 668781983. The next prime is 668782019. The reversal of 668782013 is 310287866.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-668782013 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 (668782019) 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, 1584581 + ... + 1585002.

It is an arithmetic number, because the mean of its divisors is an integer number (167987952).

Almost surely, 2^668782013 is an apocalyptic number.

It is an amenable number.

668782013 is a deficient number, since it is larger than the sum of its proper divisors (3169795).

668782013 is a wasteful number, since it uses less digits than its factorization.

668782013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3169794.

The product of its (nonzero) digits is 96768, while the sum is 41.

The square root of 668782013 is about 25860.8200372687. The cubic root of 668782013 is about 874.5034518214.

The spelling of 668782013 in words is "six hundred sixty-eight million, seven hundred eighty-two thousand, thirteen".