840749317 has 2 divisors, whose sum is σ = 840749318. Its totient is φ = 840749316.

The previous prime is 840749303. The next prime is 840749323. The reversal of 840749317 is 713947048.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 839492676 + 1256641 = 28974^2 + 1121^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-840749317 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (840749347) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 420374658 + 420374659.

It is an arithmetic number, because the mean of its divisors is an integer number (420374659).

Almost surely, 2^840749317 is an apocalyptic number.

It is an amenable number.

840749317 is a deficient number, since it is larger than the sum of its proper divisors (1).

840749317 is an equidigital number, since it uses as much as digits as its factorization.

840749317 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 169344, while the sum is 43.

The square root of 840749317 is about 28995.6775571808. The cubic root of 840749317 is about 943.8192720698.

The spelling of 840749317 in words is "eight hundred forty million, seven hundred forty-nine thousand, three hundred seventeen".