840999281 has 2 divisors, whose sum is σ = 840999282. Its totient is φ = 840999280.

The previous prime is 840999259. The next prime is 840999311. The reversal of 840999281 is 182999048.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 479391025 + 361608256 = 21895^2 + 19016^2 .

It is a cyclic number.

It is not a de Polignac number, because 840999281 - 2¹⁴ = 840982897 is a prime.

It is a super-2 number, since 2×840999281² = 1414559581285033922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (840999221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 420499640 + 420499641.

It is an arithmetic number, because the mean of its divisors is an integer number (420499641).

Almost surely, 2^840999281 is an apocalyptic number.

It is an amenable number.

840999281 is a deficient number, since it is larger than the sum of its proper divisors (1).

840999281 is an equidigital number, since it uses as much as digits as its factorization.

840999281 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 373248, while the sum is 50.

The square root of 840999281 is about 28999.9876034456. The cubic root of 840999281 is about 943.9127987445.

The spelling of 840999281 in words is "eight hundred forty million, nine hundred ninety-nine thousand, two hundred eighty-one".