64442864640 has 1056 divisors, whose sum is σ = 271243155456. Its totient is φ = 12684165120.

The previous prime is 64442864611. The next prime is 64442864687. The reversal of 64442864640 is 4646824446.

It is a tau number, because it is divible by the number of its divisors (1056).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 64442864640.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 625658829 + ... + 625658931.

Almost surely, 2^64442864640 is an apocalyptic number.

64442864640 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 64442864640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (135621577728).

64442864640 is an abundant number, since it is smaller than the sum of its proper divisors (206800290816).

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

64442864640 is a wasteful number, since it uses less digits than its factorization.

64442864640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195 (or 154 counting only the distinct ones).

The product of its (nonzero) digits is 3538944, while the sum is 48.

The spelling of 64442864640 in words is "sixty-four billion, four hundred forty-two million, eight hundred sixty-four thousand, six hundred forty".