691566984 has 80 divisors (see below), whose sum is σ = 1941302220. Its totient is φ = 230014080.

The previous prime is 691566971. The next prime is 691567007. The reversal of 691566984 is 489665196.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 377214084 + 314352900 = 19422^2 + 17730^2 .

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 691566984.

It is an unprimeable number.

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 19 ways as a sum of consecutive naturals, for example, 396354 + ... + 398094.

Almost surely, 2^691566984 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 691566984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (970651110).

691566984 is an abundant number, since it is smaller than the sum of its proper divisors (1249735236).

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

691566984 is a wasteful number, since it uses less digits than its factorization.

691566984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2372 (or 2359 counting only the distinct ones).

The product of its digits is 2799360, while the sum is 54.

The square root of 691566984 is about 26297.6611887825. The cubic root of 691566984 is about 884.3240112262.

The spelling of 691566984 in words is "six hundred ninety-one million, five hundred sixty-six thousand, nine hundred eighty-four".