6405800856 has 128 divisors (see below), whose sum is σ = 20004794880. Its totient is φ = 1664188416.

The previous prime is 6405800831. The next prime is 6405800887. The reversal of 6405800856 is 6580085046.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

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, 124440 + ... + 168216.

It is an arithmetic number, because the mean of its divisors is an integer number (156287460).

Almost surely, 2^6405800856 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6405800856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10002397440).

6405800856 is an abundant number, since it is smaller than the sum of its proper divisors (13598994024).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6405800856 is a wasteful number, since it uses less digits than its factorization.

6405800856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43873 (or 43869 counting only the distinct ones).

The product of its (nonzero) digits is 230400, while the sum is 42.

The square root of 6405800856 is about 80036.2471384060. The cubic root of 6405800856 is about 1857.1963054801.

The spelling of 6405800856 in words is "six billion, four hundred five million, eight hundred thousand, eight hundred fifty-six".