691722697 has 2 divisors, whose sum is σ = 691722698. Its totient is φ = 691722696.

The previous prime is 691722637. The next prime is 691722739. The reversal of 691722697 is 796227196.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 631567161 + 60155536 = 25131^2 + 7756^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-691722697 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 691722697.

It is not a weakly prime, because it can be changed into another prime (691722637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345861348 + 345861349.

It is an arithmetic number, because the mean of its divisors is an integer number (345861349).

Almost surely, 2^691722697 is an apocalyptic number.

It is an amenable number.

691722697 is a deficient number, since it is larger than the sum of its proper divisors (1).

691722697 is an equidigital number, since it uses as much as digits as its factorization.

691722697 is an evil number, because the sum of its binary digits is even.

The product of its digits is 571536, while the sum is 49.

The square root of 691722697 is about 26300.6216086236. The cubic root of 691722697 is about 884.3903776155.

The spelling of 691722697 in words is "six hundred ninety-one million, seven hundred twenty-two thousand, six hundred ninety-seven".