2931221 has 2 divisors, whose sum is σ = 2931222. Its totient is φ = 2931220.

The previous prime is 2931217. The next prime is 2931223. The reversal of 2931221 is 1221392.

2931221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2146225 + 784996 = 1465^2 + 886^2 .

It is a cyclic number.

It is not a de Polignac number, because 2931221 - 2² = 2931217 is a prime.

It is a Sophie Germain prime.

Together with 2931223, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 2931193 and 2931202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2931223) 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 as a sum of consecutive naturals, namely, 1465610 + 1465611.

It is an arithmetic number, because the mean of its divisors is an integer number (1465611).

2^2931221 is an apocalyptic number.

It is an amenable number.

2931221 is a deficient number, since it is larger than the sum of its proper divisors (1).

2931221 is an equidigital number, since it uses as much as digits as its factorization.

2931221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 216, while the sum is 20.

The square root of 2931221 is about 1712.0808976214. The cubic root of 2931221 is about 143.1142419277.

It can be divided in two parts, 293 and 1221, that multiplied together give a palindrome (357753).

The spelling of 2931221 in words is "two million, nine hundred thirty-one thousand, two hundred twenty-one".