691009049 has 2 divisors, whose sum is σ = 691009050. Its totient is φ = 691009048.

The previous prime is 691009031. The next prime is 691009061. The reversal of 691009049 is 940900196.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 669153424 + 21855625 = 25868^2 + 4675^2 .

It is a cyclic number.

It is not a de Polignac number, because 691009049 - 2²⁰ = 689960473 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (691009019) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345504524 + 345504525.

It is an arithmetic number, because the mean of its divisors is an integer number (345504525).

Almost surely, 2^691009049 is an apocalyptic number.

It is an amenable number.

691009049 is a deficient number, since it is larger than the sum of its proper divisors (1).

691009049 is an equidigital number, since it uses as much as digits as its factorization.

691009049 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17496, while the sum is 38.

The square root of 691009049 is about 26287.0509757181. The cubic root of 691009049 is about 884.0861320940.

The spelling of 691009049 in words is "six hundred ninety-one million, nine thousand, forty-nine".