6721643616 has 48 divisors (see below), whose sum is σ = 17649839088. Its totient is φ = 2239846400.

The previous prime is 6721643611. The next prime is 6721643629. The reversal of 6721643616 is 6163461276.

It is a tau number, because it is divible by the number of its divisors (48).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6721643611) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 363556 + ... + 381596.

It is an arithmetic number, because the mean of its divisors is an integer number (367704981).

Almost surely, 2^6721643616 is an apocalyptic number.

It is an amenable number.

6721643616 is an abundant number, since it is smaller than the sum of its proper divisors (10928195472).

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

6721643616 is a wasteful number, since it uses less digits than its factorization.

6721643616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21935 (or 21927 counting only the distinct ones).

The product of its digits is 217728, while the sum is 42.

The square root of 6721643616 is about 81985.6305458463. The cubic root of 6721643616 is about 1887.2314303253.

The spelling of 6721643616 in words is "six billion, seven hundred twenty-one million, six hundred forty-three thousand, six hundred sixteen".