6666938880 has 640 divisors, whose sum is σ = 26304030720. Its totient is φ = 1406730240.

The previous prime is 6666938821. The next prime is 6666938897. The reversal of 6666938880 is 888396666.

It is a tau number, because it is divible by the number of its divisors (640).

It is a Harshad number since it is a multiple of its sum of digits (60).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 62307787 + ... + 62307893.

It is an arithmetic number, because the mean of its divisors is an integer number (41100048).

Almost surely, 2^6666938880 is an apocalyptic number.

6666938880 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 6666938880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13152015360).

6666938880 is an abundant number, since it is smaller than the sum of its proper divisors (19637091840).

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

6666938880 is a wasteful number, since it uses less digits than its factorization.

6666938880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220 (or 204 counting only the distinct ones).

The product of its (nonzero) digits is 17915904, while the sum is 60.

The square root of 6666938880 is about 81651.3250351763. The cubic root of 6666938880 is about 1882.0976736688.

The spelling of 6666938880 in words is "six billion, six hundred sixty-six million, nine hundred thirty-eight thousand, eight hundred eighty".