3991121 has 8 divisors (see below), whose sum is σ = 4384320. Its totient is φ = 3616272.

The previous prime is 3991111. The next prime is 3991139. The reversal of 3991121 is 1211993.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 3991121 - 2¹⁰ = 3990097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3991111) 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, 4130 + ... + 5003.

It is an arithmetic number, because the mean of its divisors is an integer number (548040).

Almost surely, 2^3991121 is an apocalyptic number.

It is an amenable number.

3991121 is a deficient number, since it is larger than the sum of its proper divisors (393199).

3991121 is a wasteful number, since it uses less digits than its factorization.

3991121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9175.

The product of its digits is 486, while the sum is 26.

The square root of 3991121 is about 1997.7790168084. The cubic root of 3991121 is about 158.6225637335.

The spelling of 3991121 in words is "three million, nine hundred ninety-one thousand, one hundred twenty-one".