64445660640 has 576 divisors, whose sum is σ = 240054010560. Its totient is φ = 16303472640.

The previous prime is 64445660627. The next prime is 64445660693. The reversal of 64445660640 is 4606654446.

64445660640 is a `hidden beast` number, since 6 + 4 + 44 + 566 + 0 + 6 + 40 = 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 95 ways as a sum of consecutive naturals, for example, 68778252 + ... + 68779188.

It is an arithmetic number, because the mean of its divisors is an integer number (416760435).

Almost surely, 2^64445660640 is an apocalyptic number.

64445660640 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 64445660640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120027005280).

64445660640 is an abundant number, since it is smaller than the sum of its proper divisors (175608349920).

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

64445660640 is a wasteful number, since it uses less digits than its factorization.

64445660640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1057 (or 1037 counting only the distinct ones).

The product of its (nonzero) digits is 1658880, while the sum is 45.

The spelling of 64445660640 in words is "sixty-four billion, four hundred forty-five million, six hundred sixty thousand, six hundred forty".