6638768720 has 80 divisors (see below), whose sum is σ = 16286160000. Its totient is φ = 2509761024.

The previous prime is 6638768687. The next prime is 6638768789. The reversal of 6638768720 is 278678366.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 662306 + ... + 672254.

It is an arithmetic number, because the mean of its divisors is an integer number (203577000).

Almost surely, 2^6638768720 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 6638768720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8143080000).

6638768720 is an abundant number, since it is smaller than the sum of its proper divisors (9647391280).

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

6638768720 is a wasteful number, since it uses less digits than its factorization.

6638768720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10420 (or 10414 counting only the distinct ones).

The product of its (nonzero) digits is 4064256, while the sum is 53.

The square root of 6638768720 is about 81478.6396548200. The cubic root of 6638768720 is about 1879.4430899100.

The spelling of 6638768720 in words is "six billion, six hundred thirty-eight million, seven hundred sixty-eight thousand, seven hundred twenty".