6638849860 has 24 divisors (see below), whose sum is σ = 14761678680. Its totient is φ = 2499331584.

The previous prime is 6638849849. The next prime is 6638849863. The reversal of 6638849860 is 689488366.

It can be written as a sum of positive squares in 4 ways, for example, as 443270916 + 6195578944 = 21054^2 + 78712^2 .

It is a junction number, because it is equal to n+sod(n) for n = 6638849795 and 6638849804.

It is not an unprimeable number, because it can be changed into a prime (6638849863) 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 7 ways as a sum of consecutive naturals, for example, 9762675 + ... + 9763354.

It is an arithmetic number, because the mean of its divisors is an integer number (615069945).

Almost surely, 2^6638849860 is an apocalyptic number.

It is an amenable number.

6638849860 is an abundant number, since it is smaller than the sum of its proper divisors (8122828820).

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

6638849860 is a wasteful number, since it uses less digits than its factorization.

6638849860 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19526055 (or 19526053 counting only the distinct ones).

The product of its (nonzero) digits is 11943936, while the sum is 58.

The square root of 6638849860 is about 81479.1375752100. The cubic root of 6638849860 is about 1879.4507468213.

The spelling of 6638849860 in words is "six billion, six hundred thirty-eight million, eight hundred forty-nine thousand, eight hundred sixty".