640086843 has 32 divisors (see below), whose sum is σ = 961735680. Its totient is φ = 375330560.

The previous prime is 640086841. The next prime is 640086893. The reversal of 640086843 is 348680046.

It is not a de Polignac number, because 640086843 - 2¹ = 640086841 is a prime.

It is a super-2 number, since 2×640086843² = 819422333163413298, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (640086841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 135721 + ... + 140357.

It is an arithmetic number, because the mean of its divisors is an integer number (30054240).

Almost surely, 2^640086843 is an apocalyptic number.

640086843 is a deficient number, since it is larger than the sum of its proper divisors (321648837).

640086843 is a wasteful number, since it uses less digits than its factorization.

640086843 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4787.

The product of its (nonzero) digits is 110592, while the sum is 39.

The square root of 640086843 is about 25299.9376086187. The cubic root of 640086843 is about 861.8128529106.

The spelling of 640086843 in words is "six hundred forty million, eighty-six thousand, eight hundred forty-three".