6638539680 has 240 divisors, whose sum is σ = 24448241664. Its totient is φ = 1693232640.

The previous prime is 6638539679. The next prime is 6638539681. The reversal of 6638539680 is 869358366.

It is an interprime number because it is at equal distance from previous prime (6638539679) and next prime (6638539681).

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (6638539681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 286945 + ... + 309215.

Almost surely, 2^6638539680 is an apocalyptic number.

6638539680 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 6638539680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12224120832).

6638539680 is an abundant number, since it is smaller than the sum of its proper divisors (17809701984).

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

6638539680 is a wasteful number, since it uses less digits than its factorization.

6638539680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22321 (or 22304 counting only the distinct ones).

The product of its (nonzero) digits is 5598720, while the sum is 54.

The square root of 6638539680 is about 81477.2341209494. The cubic root of 6638539680 is about 1879.4214758319.

The spelling of 6638539680 in words is "six billion, six hundred thirty-eight million, five hundred thirty-nine thousand, six hundred eighty".