840999999 has 32 divisors (see below), whose sum is σ = 1311860736. Its totient is φ = 469244160.

The previous prime is 840999989. The next prime is 841000001. The reversal of 840999999 is 999999048.

It is a happy number.

It is a Cunningham number, because it is equal to 29000²-1.

It is not a de Polignac number, because 840999999 - 2⁷ = 840999871 is a prime.

840999999 is a modest number, since divided by 99999 gives 8409 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (840999949) 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 in 31 ways as a sum of consecutive naturals, for example, 608289 + ... + 609669.

It is an arithmetic number, because the mean of its divisors is an integer number (40995648).

Almost surely, 2^840999999 is an apocalyptic number.

840999999 is a deficient number, since it is larger than the sum of its proper divisors (470860737).

840999999 is a wasteful number, since it uses less digits than its factorization.

840999999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2055.

The product of its (nonzero) digits is 17006112, while the sum is 66.

The square root of 840999999 is about 28999.9999827586. Note that the first 4 decimals coincide. The cubic root of 840999999 is about 943.9130673651.

The spelling of 840999999 in words is "eight hundred forty million, nine hundred ninety-nine thousand, nine hundred ninety-nine".