691121 has 2 divisors, whose sum is σ = 691122. Its totient is φ = 691120.

The previous prime is 691111. The next prime is 691129. The reversal of 691121 is 121196.

691121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 664225 + 26896 = 815^2 + 164^2 .

It is a cyclic number.

It is not a de Polignac number, because 691121 - 2¹⁸ = 428977 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 691093 and 691102.

It is not a weakly prime, because it can be changed into another prime (691129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345560 + 345561.

It is an arithmetic number, because the mean of its divisors is an integer number (345561).

2⁶⁹¹¹²¹ is an apocalyptic number.

It is an amenable number.

691121 is a deficient number, since it is larger than the sum of its proper divisors (1).

691121 is an equidigital number, since it uses as much as digits as its factorization.

691121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 108, while the sum is 20.

The square root of 691121 is about 831.3368751595. The cubic root of 691121 is about 88.4133873380.

The spelling of 691121 in words is "six hundred ninety-one thousand, one hundred twenty-one".