6639999366 has 128 divisors (see below), whose sum is σ = 18879630336. Its totient is φ = 1498337280.

The previous prime is 6639999269. The next prime is 6639999403.

6639999366 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (66).

It is a junction number, because it is equal to n+sod(n) for n = 6639999297 and 6639999306.

It is a congruent number.

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, 69586 + ... + 134618.

It is an arithmetic number, because the mean of its divisors is an integer number (147497112).

Almost surely, 2^6639999366 is an apocalyptic number.

6639999366 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 6639999366, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9439815168).

6639999366 is an abundant number, since it is smaller than the sum of its proper divisors (12239630970).

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

6639999366 is a wasteful number, since it uses less digits than its factorization.

6639999366 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 65086.

The product of its digits is 76527504, while the sum is 66.

The square root of 6639999366 is about 81486.1912596239. The cubic root of 6639999366 is about 1879.5592151693.

The spelling of 6639999366 in words is "six billion, six hundred thirty-nine million, nine hundred ninety-nine thousand, three hundred sixty-six".