3991013728 has 96 divisors (see below), whose sum is σ = 8858808000. Its totient is φ = 1756102656.

The previous prime is 3991013717. The next prime is 3991013729. The reversal of 3991013728 is 8273101993.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3991013729) 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, 4295568 + ... + 4296496.

It is an arithmetic number, because the mean of its divisors is an integer number (92279250).

Almost surely, 2^3991013728 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 3991013728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4429404000).

3991013728 is an abundant number, since it is smaller than the sum of its proper divisors (4867794272).

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

3991013728 is a wasteful number, since it uses less digits than its factorization.

3991013728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1424 (or 1416 counting only the distinct ones).

The product of its (nonzero) digits is 81648, while the sum is 43.

The square root of 3991013728 is about 63174.4705399262. The cubic root of 3991013728 is about 1586.2114258621.

The spelling of 3991013728 in words is "three billion, nine hundred ninety-one million, thirteen thousand, seven hundred twenty-eight".