691328 has 32 divisors (see below), whose sum is σ = 1505520. Its totient is φ = 313600.

The previous prime is 691309. The next prime is 691333. The reversal of 691328 is 823196.

It is a tau number, because it is divible by the number of its divisors (32).

It is a self number, because there is not a number n which added to its sum of digits gives 691328.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 691328.

It is an unprimeable number.

691328 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1163 + ... + 1653.

2⁶⁹¹³²⁸ 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 691328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (752760).

691328 is an abundant number, since it is smaller than the sum of its proper divisors (814192).

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

691328 is a wasteful number, since it uses less digits than its factorization.

691328 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 516 (or 504 counting only the distinct ones).

The product of its digits is 2592, while the sum is 29.

The square root of 691328 is about 831.4613641054. The cubic root of 691328 is about 88.4222134549.

The spelling of 691328 in words is "six hundred ninety-one thousand, three hundred twenty-eight".