840451817 has 2 divisors, whose sum is σ = 840451818. Its totient is φ = 840451816.

The previous prime is 840451783. The next prime is 840451823. The reversal of 840451817 is 718154048.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 821624896 + 18826921 = 28664^2 + 4339^2 .

It is a cyclic number.

It is not a de Polignac number, because 840451817 - 2⁸ = 840451561 is a prime.

It is not a weakly prime, because it can be changed into another prime (840451867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 420225908 + 420225909.

It is an arithmetic number, because the mean of its divisors is an integer number (420225909).

Almost surely, 2^840451817 is an apocalyptic number.

It is an amenable number.

840451817 is a deficient number, since it is larger than the sum of its proper divisors (1).

840451817 is an equidigital number, since it uses as much as digits as its factorization.

840451817 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 35840, while the sum is 38.

The square root of 840451817 is about 28990.5470282987. The cubic root of 840451817 is about 943.7079351337.

The spelling of 840451817 in words is "eight hundred forty million, four hundred fifty-one thousand, eight hundred seventeen".