691431 has 8 divisors (see below), whose sum is σ = 992880. Its totient is φ = 425472.

The previous prime is 691409. The next prime is 691433. The reversal of 691431 is 134196.

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

It is not a de Polignac number, because 691431 - 2⁵ = 691399 is a prime.

It is a super-2 number, since 2×691431² = 956153655522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691433) by changing a digit.

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, 8826 + ... + 8903.

It is an arithmetic number, because the mean of its divisors is an integer number (124110).

2⁶⁹¹⁴³¹ is an apocalyptic number.

691431 is a deficient number, since it is larger than the sum of its proper divisors (301449).

691431 is a wasteful number, since it uses less digits than its factorization.

691431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17745.

The product of its digits is 648, while the sum is 24.

The square root of 691431 is about 831.5233009363. The cubic root of 691431 is about 88.4266045379.

The spelling of 691431 in words is "six hundred ninety-one thousand, four hundred thirty-one".