840478761 has 20 divisors (see below), whose sum is σ = 1265431552. Its totient is φ = 555900408.

The previous prime is 840478739. The next prime is 840478781. The reversal of 840478761 is 167874048.

It is not a de Polignac number, because 840478761 - 2⁵ = 840478729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (840478781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 30565 + ... + 51138.

Almost surely, 2^840478761 is an apocalyptic number.

840478761 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

It is an amenable number.

840478761 is a deficient number, since it is larger than the sum of its proper divisors (424952791).

840478761 is a wasteful number, since it uses less digits than its factorization.

840478761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81842 (or 81833 counting only the distinct ones).

The product of its (nonzero) digits is 301056, while the sum is 45.

The square root of 840478761 is about 28991.0117277752. The cubic root of 840478761 is about 943.7180197868.

The spelling of 840478761 in words is "eight hundred forty million, four hundred seventy-eight thousand, seven hundred sixty-one".