691279644 has 24 divisors (see below), whose sum is σ = 1759621248. Its totient is φ = 209478640.

The previous prime is 691279627. The next prime is 691279649. The reversal of 691279644 is 446972196.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 691279593 and 691279602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691279649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2618352 + ... + 2618615.

It is an arithmetic number, because the mean of its divisors is an integer number (73317552).

Almost surely, 2^691279644 is an apocalyptic number.

It is an amenable number.

691279644 is an abundant number, since it is smaller than the sum of its proper divisors (1068341604).

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

691279644 is a wasteful number, since it uses less digits than its factorization.

691279644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5236985 (or 5236983 counting only the distinct ones).

The product of its digits is 653184, while the sum is 48.

The square root of 691279644 is about 26292.1973977072. The cubic root of 691279644 is about 884.2015179765.

The spelling of 691279644 in words is "six hundred ninety-one million, two hundred seventy-nine thousand, six hundred forty-four".