691028 has 24 divisors (see below), whose sum is σ = 1325352. Its totient is φ = 313344.

The previous prime is 691001. The next prime is 691037. The reversal of 691028 is 820196.

It can be written as a sum of positive squares in 4 ways, for example, as 31684 + 659344 = 178^2 + 812^2 .

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a junction number, because it is equal to n+sod(n) for n = 690988 and 691006.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4976 + ... + 5112.

It is an arithmetic number, because the mean of its divisors is an integer number (55223).

2⁶⁹¹⁰²⁸ is an apocalyptic number.

It is an amenable number.

691028 is a deficient number, since it is larger than the sum of its proper divisors (634324).

691028 is a wasteful number, since it uses less digits than its factorization.

691028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 251 (or 249 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 691028 is about 831.2809392738. The cubic root of 691028 is about 88.4094214074.

The spelling of 691028 in words is "six hundred ninety-one thousand, twenty-eight".