3991284 has 36 divisors (see below), whose sum is σ = 11007360. Its totient is φ = 1209360.

The previous prime is 3991279. The next prime is 3991289. The reversal of 3991284 is 4821993.

It is an interprime number because it is at equal distance from previous prime (3991279) and next prime (3991289).

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3991289) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4644 + ... + 5435.

It is an arithmetic number, because the mean of its divisors is an integer number (305760).

Almost surely, 2^3991284 is an apocalyptic number.

It is an amenable number.

3991284 is an abundant number, since it is smaller than the sum of its proper divisors (7016076).

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

3991284 is a wasteful number, since it uses less digits than its factorization.

3991284 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10100 (or 10095 counting only the distinct ones).

The product of its digits is 15552, while the sum is 36.

The square root of 3991284 is about 1997.8198116947. The cubic root of 3991284 is about 158.6247231206.

The spelling of 3991284 in words is "three million, nine hundred ninety-one thousand, two hundred eighty-four".