691291231 has 8 divisors (see below), whose sum is σ = 730857200. Its totient is φ = 652043520.

The previous prime is 691291217. The next prime is 691291261. The reversal of 691291231 is 132192196.

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

It is not a de Polignac number, because 691291231 - 2⁵ = 691291199 is a prime.

It is a super-2 number, since 2×691291231² = 955767132114990722, 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 (691291261) 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, 75090 + ... + 83791.

It is an arithmetic number, because the mean of its divisors is an integer number (91357150).

Almost surely, 2^691291231 is an apocalyptic number.

691291231 is a deficient number, since it is larger than the sum of its proper divisors (39565969).

691291231 is a wasteful number, since it uses less digits than its factorization.

691291231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159129.

The product of its digits is 5832, while the sum is 34.

The square root of 691291231 is about 26292.4177473278. The cubic root of 691291231 is about 884.2064581797.

The spelling of 691291231 in words is "six hundred ninety-one million, two hundred ninety-one thousand, two hundred thirty-one".