78639240 has 64 divisors (see below), whose sum is σ = 239463360. Its totient is φ = 20655360.

The previous prime is 78639221. The next prime is 78639241. The reversal of 78639240 is 4293687.

It is not an unprimeable number, because it can be changed into a prime (78639241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3150 + ... + 12930.

It is an arithmetic number, because the mean of its divisors is an integer number (3741615).

Almost surely, 2^78639240 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78639240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119731680).

78639240 is an abundant number, since it is smaller than the sum of its proper divisors (160824120).

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

78639240 is a wasteful number, since it uses less digits than its factorization.

78639240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9862 (or 9858 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 39.

The square root of 78639240 is about 8867.8768597675. The cubic root of 78639240 is about 428.4298967576.

The spelling of 78639240 in words is "seventy-eight million, six hundred thirty-nine thousand, two hundred forty".