64681418646 has 64 divisors (see below), whose sum is σ = 155028431040. Its totient is φ = 19871723520.

The previous prime is 64681418621. The next prime is 64681418693.

64681418646 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a junction number, because it is equal to n+sod(n) for n = 64681418592 and 64681418601.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 394326 + ... + 533718.

It is an arithmetic number, because the mean of its divisors is an integer number (2422319235).

Almost surely, 2^64681418646 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 64681418646, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (77514215520).

64681418646 is an abundant number, since it is smaller than the sum of its proper divisors (90347012394).

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

64681418646 is a wasteful number, since it uses less digits than its factorization.

64681418646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140078 (or 140072 counting only the distinct ones).

The product of its digits is 5308416, while the sum is 54.

The spelling of 64681418646 in words is "sixty-four billion, six hundred eighty-one million, four hundred eighteen thousand, six hundred forty-six".