64538281664640 has 1536 divisors, whose sum is σ = 280739005747200. Its totient is φ = 13839068381184.

The previous prime is 64538281664609. The next prime is 64538281664677. The reversal of 64538281664640 is 4646618283546.

64538281664640 is a `hidden beast` number, since 6 + 4 + 5 + 3 + 8 + 2 + 8 + 166 + 464 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 2130453334 + ... + 2130483626.

It is an arithmetic number, because the mean of its divisors is an integer number (182772790200).

Almost surely, 2^{64538281664640} is an apocalyptic number.

64538281664640 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 64538281664640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140369502873600).

64538281664640 is an abundant number, since it is smaller than the sum of its proper divisors (216200724082560).

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

64538281664640 is a wasteful number, since it uses less digits than its factorization.

64538281664640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30456 (or 30432 counting only the distinct ones).

The product of its (nonzero) digits is 159252480, while the sum is 63.

The spelling of 64538281664640 in words is "sixty-four trillion, five hundred thirty-eight billion, two hundred eighty-one million, six hundred sixty-four thousand, six hundred forty".