691120656 has 60 divisors (see below), whose sum is σ = 1951340508. Its totient is φ = 228329472.

The previous prime is 691120607. The next prime is 691120657. The reversal of 691120656 is 656021196.

It can be written as a sum of positive squares in 2 ways, for example, as 51840000 + 639280656 = 7200^2 + 25284^2 .

It is a super-2 number, since 2×691120656² = 955295522299740672, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 691120656.

It is not an unprimeable number, because it can be changed into a prime (691120657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4965 + ... + 37508.

Almost surely, 2^691120656 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 691120656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (975670254).

691120656 is an abundant number, since it is smaller than the sum of its proper divisors (1260219852).

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

691120656 is a wasteful number, since it uses less digits than its factorization.

691120656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42600 (or 42591 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

The square root of 691120656 is about 26289.1737412951. The cubic root of 691120656 is about 884.1337266898.

The spelling of 691120656 in words is "six hundred ninety-one million, one hundred twenty thousand, six hundred fifty-six".