6405557220 has 96 divisors (see below), whose sum is σ = 20111414400. Its totient is φ = 1692461952.

The previous prime is 6405557209. The next prime is 6405557251. The reversal of 6405557220 is 227555046.

6405557220 is a `hidden beast` number, since 64 + 0 + 5 + 5 + 572 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4447 + ... + 113273.

It is an arithmetic number, because the mean of its divisors is an integer number (209493900).

Almost surely, 2^6405557220 is an apocalyptic number.

6405557220 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6405557220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10055707200).

6405557220 is an abundant number, since it is smaller than the sum of its proper divisors (13705857180).

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

6405557220 is a wasteful number, since it uses less digits than its factorization.

6405557220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108954 (or 108946 counting only the distinct ones).

The product of its (nonzero) digits is 84000, while the sum is 36.

The square root of 6405557220 is about 80034.7250885514. The cubic root of 6405557220 is about 1857.1727598623.

The spelling of 6405557220 in words is "six billion, four hundred five million, five hundred fifty-seven thousand, two hundred twenty".