840439940 has 12 divisors (see below), whose sum is σ = 1764923916. Its totient is φ = 336175968.

The previous prime is 840439927. The next prime is 840439949. The reversal of 840439940 is 49934048.

It can be written as a sum of positive squares in 2 ways, for example, as 234886276 + 605553664 = 15326^2 + 24608^2 .

It is a hoax number, since the sum of its digits (41) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (840439949) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21010979 + ... + 21011018.

It is an arithmetic number, because the mean of its divisors is an integer number (147076993).

Almost surely, 2^840439940 is an apocalyptic number.

It is an amenable number.

840439940 is an abundant number, since it is smaller than the sum of its proper divisors (924483976).

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

840439940 is a wasteful number, since it uses less digits than its factorization.

840439940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42022006 (or 42022004 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 41.

The square root of 840439940 is about 28990.3421849415. The cubic root of 840439940 is about 943.7034897185.

The spelling of 840439940 in words is "eight hundred forty million, four hundred thirty-nine thousand, nine hundred forty".