668761913 has 4 divisors (see below), whose sum is σ = 671560320. Its totient is φ = 665963508.

The previous prime is 668761909. The next prime is 668761927. The reversal of 668761913 is 319167866.

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 not a de Polignac number, because 668761913 - 2² = 668761909 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (668763913) 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, 1398845 + ... + 1399322.

It is an arithmetic number, because the mean of its divisors is an integer number (167890080).

Almost surely, 2^668761913 is an apocalyptic number.

It is an amenable number.

668761913 is a deficient number, since it is larger than the sum of its proper divisors (2798407).

668761913 is a wasteful number, since it uses less digits than its factorization.

668761913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2798406.

The product of its digits is 326592, while the sum is 47.

The square root of 668761913 is about 25860.4314155816. The cubic root of 668761913 is about 874.4946907726.

The spelling of 668761913 in words is "six hundred sixty-eight million, seven hundred sixty-one thousand, nine hundred thirteen".