840999861 has 32 divisors (see below), whose sum is σ = 1347131520. Its totient is φ = 515469312.

The previous prime is 840999851. The next prime is 840999871. The reversal of 840999861 is 168999048.

It is an interprime number because it is at equal distance from previous prime (840999851) and next prime (840999871).

It is not a de Polignac number, because 840999861 - 2¹¹ = 840997813 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 840999798 and 840999807.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (840999821) 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, 85546 + ... + 94868.

It is an arithmetic number, because the mean of its divisors is an integer number (42097860).

Almost surely, 2^840999861 is an apocalyptic number.

It is an amenable number.

840999861 is a deficient number, since it is larger than the sum of its proper divisors (506131659).

840999861 is a wasteful number, since it uses less digits than its factorization.

840999861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9602 (or 9596 counting only the distinct ones).

The product of its (nonzero) digits is 1119744, while the sum is 54.

The square root of 840999861 is about 28999.9976034482. The cubic root of 840999861 is about 943.9130157361.

The spelling of 840999861 in words is "eight hundred forty million, nine hundred ninety-nine thousand, eight hundred sixty-one".