6440779800 has 960 divisors, whose sum is σ = 29265001920. Its totient is φ = 1274019840.

The previous prime is 6440779789. The next prime is 6440779837. The reversal of 6440779800 is 89770446.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 25061272 + ... + 25061528.

It is an arithmetic number, because the mean of its divisors is an integer number (30484377).

Almost surely, 2^6440779800 is an apocalyptic number.

6440779800 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 6440779800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14632500960).

6440779800 is an abundant number, since it is smaller than the sum of its proper divisors (22824222120).

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

6440779800 is a wasteful number, since it uses less digits than its factorization.

6440779800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322 (or 304 counting only the distinct ones).

The product of its (nonzero) digits is 338688, while the sum is 45.

The square root of 6440779800 is about 80254.4690344407. The cubic root of 6440779800 is about 1860.5705845716.

The spelling of 6440779800 in words is "six billion, four hundred forty million, seven hundred seventy-nine thousand, eight hundred".