691228 has 6 divisors (see below), whose sum is σ = 1209656. Its totient is φ = 345612.

The previous prime is 691199. The next prime is 691231. The reversal of 691228 is 822196.

It is a happy number.

It is a super-2 number, since 2×691228² = 955592295968, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 691196 and 691205.

It is a congruent number.

It is an unprimeable number.

691228 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 as a sum of consecutive naturals, namely, 86400 + ... + 86407.

2⁶⁹¹²²⁸ is an apocalyptic number.

It is an amenable number.

691228 is a deficient number, since it is larger than the sum of its proper divisors (518428).

691228 is a wasteful number, since it uses less digits than its factorization.

691228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 172811 (or 172809 counting only the distinct ones).

The product of its digits is 1728, while the sum is 28.

The square root of 691228 is about 831.4012268454. The cubic root of 691228 is about 88.4179498503.

It can be divided in two parts, 691 and 228, that added together give a palindrome (919).

The spelling of 691228 in words is "six hundred ninety-one thousand, two hundred twenty-eight".