2780781840 has 400 divisors, whose sum is σ = 10140303360. Its totient is φ = 705438720.

The previous prime is 2780781823. The next prime is 2780781863. The reversal of 2780781840 is 481870872.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 21895857 + ... + 21895983.

Almost surely, 2^2780781840 is an apocalyptic number.

2780781840 is a gapful number since it is divisible by the number (20) 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 2780781840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5070151680).

2780781840 is an abundant number, since it is smaller than the sum of its proper divisors (7359521520).

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

2780781840 is a wasteful number, since it uses less digits than its factorization.

2780781840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 292 (or 277 counting only the distinct ones).

The product of its (nonzero) digits is 200704, while the sum is 45.

The square root of 2780781840 is about 52733.1190050427. The cubic root of 2780781840 is about 1406.2276711121.

The spelling of 2780781840 in words is "two billion, seven hundred eighty million, seven hundred eighty-one thousand, eight hundred forty".