691261 has 4 divisors (see below), whose sum is σ = 696832. Its totient is φ = 685692.

The previous prime is 691241. The next prime is 691267. The reversal of 691261 is 162196.

691261 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, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 691261 - 2¹⁹ = 166973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691267) 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, 2595 + ... + 2848.

It is an arithmetic number, because the mean of its divisors is an integer number (174208).

2⁶⁹¹²⁶¹ is an apocalyptic number.

It is an amenable number.

691261 is a deficient number, since it is larger than the sum of its proper divisors (5571).

691261 is a wasteful number, since it uses less digits than its factorization.

691261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5570.

The product of its digits is 648, while the sum is 25.

The square root of 691261 is about 831.4210726220. The cubic root of 691261 is about 88.4193568853.

The spelling of 691261 in words is "six hundred ninety-one thousand, two hundred sixty-one".