78256439664 has 60 divisors (see below), whose sum is σ = 218909678616. Its totient is φ = 24078902016.

The previous prime is 78256439663. The next prime is 78256439687. The reversal of 78256439664 is 46693465287.

It is a super-2 number, since 2×78256439664² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 78256439598 and 78256439607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78256439663) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4815387 + ... + 4831610.

Almost surely, 2^78256439664 is an apocalyptic number.

It is an amenable number.

78256439664 is an abundant number, since it is smaller than the sum of its proper divisors (140653238952).

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

78256439664 is a wasteful number, since it uses less digits than its factorization.

78256439664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9647034 (or 9647015 counting only the distinct ones).

The product of its digits is 52254720, while the sum is 60.

It can be divided in two parts, 782564 and 39664, that added together give a palindrome (822228).

The spelling of 78256439664 in words is "seventy-eight billion, two hundred fifty-six million, four hundred thirty-nine thousand, six hundred sixty-four".