668920749871 has 4 divisors (see below), whose sum is σ = 729731727144. Its totient is φ = 608109772600.

The previous prime is 668920749829. The next prime is 668920749877. The reversal of 668920749871 is 178947029866.

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

It is not a de Polignac number, because 668920749871 - 2¹³ = 668920741679 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 668920749797 and 668920749806.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668920749877) 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, 30405488620 + ... + 30405488641.

It is an arithmetic number, because the mean of its divisors is an integer number (182432931786).

Almost surely, 2^668920749871 is an apocalyptic number.

668920749871 is a deficient number, since it is larger than the sum of its proper divisors (60810977273).

668920749871 is a wasteful number, since it uses less digits than its factorization.

668920749871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60810977272.

The product of its (nonzero) digits is 73156608, while the sum is 67.

The spelling of 668920749871 in words is "six hundred sixty-eight billion, nine hundred twenty million, seven hundred forty-nine thousand, eight hundred seventy-one".