691375 has 8 divisors (see below), whose sum is σ = 862992. Its totient is φ = 553000.

The previous prime is 691363. The next prime is 691381. The reversal of 691375 is 573196.

It is not a de Polignac number, because 691375 - 2⁵ = 691343 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2641 + ... + 2890.

It is an arithmetic number, because the mean of its divisors is an integer number (107874).

2⁶⁹¹³⁷⁵ is an apocalyptic number.

691375 is a deficient number, since it is larger than the sum of its proper divisors (171617).

691375 is an equidigital number, since it uses as much as digits as its factorization.

691375 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5546 (or 5536 counting only the distinct ones).

The product of its digits is 5670, while the sum is 31.

The square root of 691375 is about 831.4896271151. The cubic root of 691375 is about 88.4242172071.

It can be divided in two parts, 69 and 1375, that added together give a square (1444 = 38²).

The spelling of 691375 in words is "six hundred ninety-one thousand, three hundred seventy-five".