6621688878 has 64 divisors (see below), whose sum is σ = 15477972480. Its totient is φ = 1849341312.

The previous prime is 6621688873. The next prime is 6621688903. The reversal of 6621688878 is 8788861266.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6621688873) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 611233 + ... + 621971.

It is an arithmetic number, because the mean of its divisors is an integer number (241843320).

Almost surely, 2^6621688878 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6621688878, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7738986240).

6621688878 is an abundant number, since it is smaller than the sum of its proper divisors (8856283602).

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

6621688878 is a wasteful number, since it uses less digits than its factorization.

6621688878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11081.

The product of its digits is 12386304, while the sum is 60.

The square root of 6621688878 is about 81373.7603776549. The cubic root of 6621688878 is about 1877.8299313739.

The spelling of 6621688878 in words is "six billion, six hundred twenty-one million, six hundred eighty-eight thousand, eight hundred seventy-eight".