6644821764 has 48 divisors (see below), whose sum is σ = 17772180608. Its totient is φ = 1892878848.

The previous prime is 6644821763. The next prime is 6644821783. The reversal of 6644821764 is 4671284466.

It is not an unprimeable number, because it can be changed into a prime (6644821763) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 89059 + ... + 145674.

Almost surely, 2^6644821764 is an apocalyptic number.

It is an amenable number.

6644821764 is an abundant number, since it is smaller than the sum of its proper divisors (11127358844).

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

6644821764 is a wasteful number, since it uses less digits than its factorization.

6644821764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 235084 (or 235082 counting only the distinct ones).

The product of its digits is 1548288, while the sum is 48.

The square root of 6644821764 is about 81515.7761663348. The cubic root of 6644821764 is about 1880.0141243092.

The spelling of 6644821764 in words is "six billion, six hundred forty-four million, eight hundred twenty-one thousand, seven hundred sixty-four".