3891121 has 4 divisors (see below), whose sum is σ = 4190452. Its totient is φ = 3591792.

The previous prime is 3891103. The next prime is 3891131. The reversal of 3891121 is 1211983.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1860496 + 2030625 = 1364^2 + 1425^2 .

It is a cyclic number.

It is not a de Polignac number, because 3891121 - 2⁹ = 3890609 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3891131) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 149646 + ... + 149671.

It is an arithmetic number, because the mean of its divisors is an integer number (1047613).

Almost surely, 2^3891121 is an apocalyptic number.

It is an amenable number.

3891121 is a deficient number, since it is larger than the sum of its proper divisors (299331).

3891121 is a wasteful number, since it uses less digits than its factorization.

3891121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 299330.

The product of its digits is 432, while the sum is 25.

The square root of 3891121 is about 1972.5924566418. The cubic root of 3891121 is about 157.2865471622.

The spelling of 3891121 in words is "three million, eight hundred ninety-one thousand, one hundred twenty-one".