691628 has 24 divisors (see below), whose sum is σ = 1465632. Its totient is φ = 278784.

The previous prime is 691591. The next prime is 691631. The reversal of 691628 is 826196.

Added to its reverse (826196) it gives a square (1517824 = 1232²).

691628 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (32) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 691594 and 691603.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 691628.

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, 251 + ... + 1202.

It is an arithmetic number, because the mean of its divisors is an integer number (61068).

2⁶⁹¹⁶²⁸ is an apocalyptic number.

691628 is a gapful number since it is divisible by the number (68) formed by its first and last digit.

It is an amenable number.

691628 is an abundant number, since it is smaller than the sum of its proper divisors (774004).

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

691628 is a wasteful number, since it uses less digits than its factorization.

691628 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1481 (or 1479 counting only the distinct ones).

The product of its digits is 5184, while the sum is 32.

The square root of 691628 is about 831.6417497937. The cubic root of 691628 is about 88.4350018023.

Adding to 691628 its reverse (826196), we get a square (1517824 = 1232²).

The spelling of 691628 in words is "six hundred ninety-one thousand, six hundred twenty-eight".