64228868640 has 144 divisors (see below), whose sum is σ = 219267554688. Its totient is φ = 17120936448.

The previous prime is 64228868633. The next prime is 64228868651. The reversal of 64228868640 is 4686882246.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4409209 + ... + 4423751.

It is an arithmetic number, because the mean of its divisors is an integer number (1522691352).

Almost surely, 2^64228868640 is an apocalyptic number.

64228868640 is a gapful number since it is divisible by the number (60) 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 64228868640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109633777344).

64228868640 is an abundant number, since it is smaller than the sum of its proper divisors (155038686048).

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

64228868640 is a wasteful number, since it uses less digits than its factorization.

64228868640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17631 (or 17620 counting only the distinct ones).

The product of its (nonzero) digits is 7077888, while the sum is 54.

The spelling of 64228868640 in words is "sixty-four billion, two hundred twenty-eight million, eight hundred sixty-eight thousand, six hundred forty".