6518721972 has 96 divisors (see below), whose sum is σ = 17641451520. Its totient is φ = 1834934400.

The previous prime is 6518721949. The next prime is 6518721991. The reversal of 6518721972 is 2791278156.

It is a super-2 number, since 2×6518721972² = 84987472296471137568, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4491847 + ... + 4493297.

It is an arithmetic number, because the mean of its divisors is an integer number (183765120).

Almost surely, 2^6518721972 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6518721972, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8820725760).

6518721972 is an abundant number, since it is smaller than the sum of its proper divisors (11122729548).

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

6518721972 is a wasteful number, since it uses less digits than its factorization.

6518721972 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2221 (or 2219 counting only the distinct ones).

The product of its digits is 423360, while the sum is 48.

The square root of 6518721972 is about 80738.6027374762. The cubic root of 6518721972 is about 1868.0456549390.

The spelling of 6518721972 in words is "six billion, five hundred eighteen million, seven hundred twenty-one thousand, nine hundred seventy-two".