840781440 has 96 divisors (see below), whose sum is σ = 2903343300. Its totient is φ = 224206848.

The previous prime is 840781433. The next prime is 840781463. The reversal of 840781440 is 44187048.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 817045056 + 23736384 = 28584^2 + 4872^2 .

It is a tau number, because it is divible by the number of its divisors (96).

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 = 840781395 and 840781404.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 67225 + ... + 78744.

Almost surely, 2^840781440 is an apocalyptic number.

840781440 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

840781440 is an abundant number, since it is smaller than the sum of its proper divisors (2062561860).

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

840781440 is a wasteful number, since it uses less digits than its factorization.

840781440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 145994 (or 145979 counting only the distinct ones).

The product of its (nonzero) digits is 28672, while the sum is 36.

The square root of 840781440 is about 28996.2314792802. The cubic root of 840781440 is about 943.8312922680.

The spelling of 840781440 in words is "eight hundred forty million, seven hundred eighty-one thousand, four hundred forty".