3261991 has 4 divisors (see below), whose sum is σ = 3323592. Its totient is φ = 3200392.

The previous prime is 3261967. The next prime is 3262003. The reversal of 3261991 is 1991623.

3261991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 3261991 - 2¹³ = 3253799 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax 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 (3261911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30721 + ... + 30826.

It is an arithmetic number, because the mean of its divisors is an integer number (830898).

Almost surely, 2^3261991 is an apocalyptic number.

3261991 is a deficient number, since it is larger than the sum of its proper divisors (61601).

3261991 is an equidigital number, since it uses as much as digits as its factorization.

3261991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61600.

The product of its digits is 2916, while the sum is 31.

The square root of 3261991 is about 1806.0982808253. The cubic root of 3261991 is about 148.3067505563.

The spelling of 3261991 in words is "three million, two hundred sixty-one thousand, nine hundred ninety-one".