691776 has 42 divisors (see below), whose sum is σ = 1984502. Its totient is φ = 230400.

The previous prime is 691763. The next prime is 691787. The reversal of 691776 is 677196.

It can be written as a sum of positive squares in only one way, i.e., 360000 + 331776 = 600^2 + 576^2 .

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 691776.

It is a congruent number.

It is an unprimeable number.

691776 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 25 + ... + 1176.

2⁶⁹¹⁷⁷⁶ 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 691776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (992251).

691776 is an abundant number, since it is smaller than the sum of its proper divisors (1292726).

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

691776 is a wasteful number, since it uses less digits than its factorization.

691776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1219 (or 1206 counting only the distinct ones).

The product of its digits is 15876, while the sum is 36.

The square root of 691776 is about 831.7307256558. The cubic root of 691776 is about 88.4413093582.

The spelling of 691776 in words is "six hundred ninety-one thousand, seven hundred seventy-six".