64643457750520 has 128 divisors (see below), whose sum is σ = 161792256384000. Its totient is φ = 23046337082880.

The previous prime is 64643457750517. The next prime is 64643457750527. The reversal of 64643457750520 is 2505775434646.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64643457750527) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6345121 + ... + 13021039.

It is an arithmetic number, because the mean of its divisors is an integer number (1264002003000).

Almost surely, 2^{64643457750520} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 64643457750520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (80896128192000).

64643457750520 is an abundant number, since it is smaller than the sum of its proper divisors (97148798633480).

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

64643457750520 is a wasteful number, since it uses less digits than its factorization.

64643457750520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6676373 (or 6676369 counting only the distinct ones).

The product of its (nonzero) digits is 84672000, while the sum is 58.

The spelling of 64643457750520 in words is "sixty-four trillion, six hundred forty-three billion, four hundred fifty-seven million, seven hundred fifty thousand, five hundred twenty".