691668861739 has 4 divisors (see below), whose sum is σ = 703007695600. Its totient is φ = 680330027880.

The previous prime is 691668861641. The next prime is 691668861811. The reversal of 691668861739 is 937168866196.

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

It is a cyclic number.

It is not a de Polignac number, because 691668861739 - 2⁹ = 691668861227 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (691668861139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5669416839 + ... + 5669416960.

It is an arithmetic number, because the mean of its divisors is an integer number (175751923900).

Almost surely, 2^691668861739 is an apocalyptic number.

691668861739 is a deficient number, since it is larger than the sum of its proper divisors (11338833861).

691668861739 is a wasteful number, since it uses less digits than its factorization.

691668861739 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11338833860.

The product of its digits is 141087744, while the sum is 70.

The spelling of 691668861739 in words is "six hundred ninety-one billion, six hundred sixty-eight million, eight hundred sixty-one thousand, seven hundred thirty-nine".