691291 has 4 divisors (see below), whose sum is σ = 693000. Its totient is φ = 689584.

The previous prime is 691289. The next prime is 691297. The reversal of 691291 is 192196.

691291 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 691291 - 2¹ = 691289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (691297) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 135 + ... + 1183.

It is an arithmetic number, because the mean of its divisors is an integer number (173250).

2⁶⁹¹²⁹¹ is an apocalyptic number.

691291 is a deficient number, since it is larger than the sum of its proper divisors (1709).

691291 is a wasteful number, since it uses less digits than its factorization.

691291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1708.

The product of its digits is 972, while the sum is 28.

The square root of 691291 is about 831.4391138261. The cubic root of 691291 is about 88.4206359692.

The spelling of 691291 in words is "six hundred ninety-one thousand, two hundred ninety-one".