6781312440 has 256 divisors, whose sum is σ = 26725248000. Its totient is φ = 1496517120.

The previous prime is 6781312379. The next prime is 6781312451. The reversal of 6781312440 is 442131876.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 6781312395 and 6781312404.

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, 203775 + ... + 234705.

It is an arithmetic number, because the mean of its divisors is an integer number (104395500).

Almost surely, 2^6781312440 is an apocalyptic number.

6781312440 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 6781312440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13362624000).

6781312440 is an abundant number, since it is smaller than the sum of its proper divisors (19943935560).

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

6781312440 is a wasteful number, since it uses less digits than its factorization.

6781312440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30987 (or 30977 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 36.

The square root of 6781312440 is about 82348.7245802872. The cubic root of 6781312440 is about 1892.7993789815.

The spelling of 6781312440 in words is "six billion, seven hundred eighty-one million, three hundred twelve thousand, four hundred forty".