6638009220 has 36 divisors (see below), whose sum is σ = 20135295180. Its totient is φ = 1770135744.

The previous prime is 6638009179. The next prime is 6638009237. The reversal of 6638009220 is 229008366.

It can be written as a sum of positive squares in 2 ways, for example, as 1430654976 + 5207354244 = 37824^2 + 72162^2 .

It is a tau number, because it is divible by the number of its divisors (36).

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 11 ways as a sum of consecutive naturals, for example, 18438735 + ... + 18439094.

It is an arithmetic number, because the mean of its divisors is an integer number (559313755).

Almost surely, 2^6638009220 is an apocalyptic number.

6638009220 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

6638009220 is an abundant number, since it is smaller than the sum of its proper divisors (13497285960).

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

6638009220 is a wasteful number, since it uses less digits than its factorization.

6638009220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36877844 (or 36877839 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 6638009220 is about 81473.9787907771. The cubic root of 6638009220 is about 1879.3714154010.

The spelling of 6638009220 in words is "six billion, six hundred thirty-eight million, nine thousand, two hundred twenty".