78439706856 has 512 divisors, whose sum is σ = 270566400000. Its totient is φ = 20986801920.

The previous prime is 78439706827. The next prime is 78439706941. The reversal of 78439706856 is 65860793487.

78439706856 is a `hidden beast` number, since 78 + 439 + 70 + 68 + 5 + 6 = 666.

It is a super-2 number, since 2×78439706856² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is a junction number, because it is equal to n+sod(n) for n = 78439706793 and 78439706802.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 144989946 + ... + 144990486.

It is an arithmetic number, because the mean of its divisors is an integer number (528450000).

Almost surely, 2^78439706856 is an apocalyptic number.

78439706856 is a gapful number since it is divisible by the number (76) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78439706856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135283200000).

78439706856 is an abundant number, since it is smaller than the sum of its proper divisors (192126693144).

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

78439706856 is a wasteful number, since it uses less digits than its factorization.

78439706856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 699 (or 675 counting only the distinct ones).

The product of its (nonzero) digits is 60963840, while the sum is 63.

The spelling of 78439706856 in words is "seventy-eight billion, four hundred thirty-nine million, seven hundred six thousand, eight hundred fifty-six".