691969 has 8 divisors (see below), whose sum is σ = 725760. Its totient is φ = 658896.

The previous prime is 691949. The next prime is 691973. The reversal of 691969 is 969196.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 691969 - 2⁷ = 691841 is a prime.

It is a super-2 number, since 2×691969² = 957642193922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

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

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2992 + ... + 3214.

It is an arithmetic number, because the mean of its divisors is an integer number (90720).

2⁶⁹¹⁹⁶⁹ is an apocalyptic number.

It is an amenable number.

691969 is a deficient number, since it is larger than the sum of its proper divisors (33791).

691969 is a wasteful number, since it uses less digits than its factorization.

691969 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 359.

The product of its digits is 26244, while the sum is 40.

The square root of 691969 is about 831.8467406921. The cubic root of 691969 is about 88.4495334007.

The spelling of 691969 in words is "six hundred ninety-one thousand, nine hundred sixty-nine".