691959 has 4 divisors (see below), whose sum is σ = 922616. Its totient is φ = 461304.

The previous prime is 691949. The next prime is 691973. The reversal of 691959 is 959196.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 691959 - 2¹⁷ = 560887 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 691959.

It is not an unprimeable number, because it can be changed into a prime (691919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 115324 + ... + 115329.

It is an arithmetic number, because the mean of its divisors is an integer number (230654).

2⁶⁹¹⁹⁵⁹ is an apocalyptic number.

691959 is a deficient number, since it is larger than the sum of its proper divisors (230657).

691959 is a wasteful number, since it uses less digits than its factorization.

691959 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230656.

The product of its digits is 21870, while the sum is 39.

The square root of 691959 is about 831.8407299477. The cubic root of 691959 is about 88.4491073221.

The spelling of 691959 in words is "six hundred ninety-one thousand, nine hundred fifty-nine".