78405647784 has 128 divisors (see below), whose sum is σ = 209143296000. Its totient is φ = 24437160704.

The previous prime is 78405647717. The next prime is 78405647809. The reversal of 78405647784 is 48774650487.

It is a super-2 number, since 2×78405647784² (a number of 23 digits) contains 22 as substring.

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 31 ways as a sum of consecutive naturals, for example, 31883947 + ... + 31886405.

It is an arithmetic number, because the mean of its divisors is an integer number (1633932000).

Almost surely, 2^78405647784 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 78405647784, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (104571648000).

78405647784 is an abundant number, since it is smaller than the sum of its proper divisors (130737648216).

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

78405647784 is a wasteful number, since it uses less digits than its factorization.

78405647784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3767 (or 3763 counting only the distinct ones).

The product of its (nonzero) digits is 42147840, while the sum is 60.

The spelling of 78405647784 in words is "seventy-eight billion, four hundred five million, six hundred forty-seven thousand, seven hundred eighty-four".