64533978768 has 160 divisors (see below), whose sum is σ = 191590150144. Its totient is φ = 18335932416.

The previous prime is 64533978731. The next prime is 64533978791. The reversal of 64533978768 is 86787933546.

It is a junction number, because it is equal to n+sod(n) for n = 64533978699 and 64533978708.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 71150571 + ... + 71151477.

Almost surely, 2^64533978768 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 64533978768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (95795075072).

64533978768 is an abundant number, since it is smaller than the sum of its proper divisors (127056171376).

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

64533978768 is a wasteful number, since it uses less digits than its factorization.

64533978768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1869 (or 1863 counting only the distinct ones).

The product of its digits is 182891520, while the sum is 66.

The spelling of 64533978768 in words is "sixty-four billion, five hundred thirty-three million, nine hundred seventy-eight thousand, seven hundred sixty-eight".