2644688640 has 576 divisors, whose sum is σ = 10172252160. Its totient is φ = 578027520.

The previous prime is 2644688639. The next prime is 2644688687. The reversal of 2644688640 is 468864462.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 2644688640.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 20824257 + ... + 20824383.

It is an arithmetic number, because the mean of its divisors is an integer number (17660160).

Almost surely, 2^2644688640 is an apocalyptic number.

2644688640 is a gapful number since it is divisible by the number (20) 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 2644688640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5086126080).

2644688640 is an abundant number, since it is smaller than the sum of its proper divisors (7527563520).

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

2644688640 is a wasteful number, since it uses less digits than its factorization.

2644688640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 208 (or 194 counting only the distinct ones).

The product of its (nonzero) digits is 1769472, while the sum is 48.

The square root of 2644688640 is about 51426.5363406870. The cubic root of 2644688640 is about 1382.9023562191.

The spelling of 2644688640 in words is "two billion, six hundred forty-four million, six hundred eighty-eight thousand, six hundred forty".