3991872 has 56 divisors (see below), whose sum is σ = 11192256. Its totient is φ = 1251328.

The previous prime is 3991853. The next prime is 3991877. The reversal of 3991872 is 2781993.

It is a self number, because there is not a number n which added to its sum of digits gives 3991872.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3991877) 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, 2653 + ... + 3875.

Almost surely, 2^3991872 is an apocalyptic number.

3991872 is a gapful number since it is divisible by the number (32) 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 3991872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5596128).

3991872 is an abundant number, since it is smaller than the sum of its proper divisors (7200384).

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

3991872 is a wasteful number, since it uses less digits than its factorization.

3991872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1255 (or 1245 counting only the distinct ones).

The product of its digits is 27216, while the sum is 39.

The square root of 3991872 is about 1997.9669666939. The cubic root of 3991872 is about 158.6325123231.

The spelling of 3991872 in words is "three million, nine hundred ninety-one thousand, eight hundred seventy-two".