64440735840 has 960 divisors, whose sum is σ = 262792252800. Its totient is φ = 14730854400.

The previous prime is 64440735811. The next prime is 64440735871. The reversal of 64440735840 is 4853704446.

64440735840 is a `hidden beast` number, since 64 + 4 + 4 + 0 + 7 + 3 + 584 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 426759765 + ... + 426759915.

It is an arithmetic number, because the mean of its divisors is an integer number (273741930).

Almost surely, 2^64440735840 is an apocalyptic number.

64440735840 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 64440735840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (131396126400).

64440735840 is an abundant number, since it is smaller than the sum of its proper divisors (198351516960).

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

64440735840 is a wasteful number, since it uses less digits than its factorization.

64440735840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 357 (or 340 counting only the distinct ones).

The product of its (nonzero) digits is 1290240, while the sum is 45.

The spelling of 64440735840 in words is "sixty-four billion, four hundred forty million, seven hundred thirty-five thousand, eight hundred forty".