691273949 has 2 divisors, whose sum is σ = 691273950. Its totient is φ = 691273948.

The previous prime is 691273897. The next prime is 691274029. The reversal of 691273949 is 949372196.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 684607225 + 6666724 = 26165^2 + 2582^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-691273949 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 691273897 and 691273906.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (691273049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345636974 + 345636975.

It is an arithmetic number, because the mean of its divisors is an integer number (345636975).

Almost surely, 2^691273949 is an apocalyptic number.

It is an amenable number.

691273949 is a deficient number, since it is larger than the sum of its proper divisors (1).

691273949 is an equidigital number, since it uses as much as digits as its factorization.

691273949 is an evil number, because the sum of its binary digits is even.

The product of its digits is 734832, while the sum is 50.

The square root of 691273949 is about 26292.0890953914. The cubic root of 691273949 is about 884.1990898508.

The spelling of 691273949 in words is "six hundred ninety-one million, two hundred seventy-three thousand, nine hundred forty-nine".