64843964640 has 768 divisors, whose sum is σ = 280799447040. Its totient is φ = 13609451520.

The previous prime is 64843964639. The next prime is 64843964651. The reversal of 64843964640 is 4646934846.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 110466427 + ... + 110467013.

It is an arithmetic number, because the mean of its divisors is an integer number (365624280).

Almost surely, 2^64843964640 is an apocalyptic number.

64843964640 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 64843964640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (140399723520).

64843964640 is an abundant number, since it is smaller than the sum of its proper divisors (215955482400).

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

64843964640 is a wasteful number, since it uses less digits than its factorization.

64843964640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 912 (or 898 counting only the distinct ones).

The product of its (nonzero) digits is 11943936, while the sum is 54.

The spelling of 64843964640 in words is "sixty-four billion, eight hundred forty-three million, nine hundred sixty-four thousand, six hundred forty".