3129221 has 2 divisors, whose sum is σ = 3129222. Its totient is φ = 3129220.

The previous prime is 3129209. The next prime is 3129223. The reversal of 3129221 is 1229213.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1852321 + 1276900 = 1361^2 + 1130^2 .

It is an emirp because it is prime and its reverse (1229213) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3129221 - 2¹⁰ = 3128197 is a prime.

It is a Sophie Germain prime.

Together with 3129223, 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 = 3129193 and 3129202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3129223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1564610 + 1564611.

It is an arithmetic number, because the mean of its divisors is an integer number (1564611).

Almost surely, 2^3129221 is an apocalyptic number.

It is an amenable number.

3129221 is a deficient number, since it is larger than the sum of its proper divisors (1).

3129221 is an equidigital number, since it uses as much as digits as its factorization.

3129221 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 3129221 is about 1768.9604291787. The cubic root of 3129221 is about 146.2666827829.

It can be divided in two parts, 31292 and 21, that added together give a palindrome (31313).

The spelling of 3129221 in words is "three million, one hundred twenty-nine thousand, two hundred twenty-one".