691139408680 has 128 divisors (see below), whose sum is σ = 1794345696000. Its totient is φ = 234680094720.

The previous prime is 691139408507. The next prime is 691139408767. The reversal of 691139408680 is 86804931196.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 94272615 + ... + 94279945.

It is an arithmetic number, because the mean of its divisors is an integer number (14018325750).

Almost surely, 2^691139408680 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 691139408680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (897172848000).

691139408680 is an abundant number, since it is smaller than the sum of its proper divisors (1103206287320).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

691139408680 is a wasteful number, since it uses less digits than its factorization.

691139408680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10547 (or 10543 counting only the distinct ones).

The product of its (nonzero) digits is 2239488, while the sum is 55.

The spelling of 691139408680 in words is "six hundred ninety-one billion, one hundred thirty-nine million, four hundred eight thousand, six hundred eighty".