381221 has 2 divisors, whose sum is σ = 381222. Its totient is φ = 381220.

The previous prime is 381209. The next prime is 381223. The reversal of 381221 is 122183.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 376996 + 4225 = 614^2 + 65^2 .

It is a cyclic number.

It is not a de Polignac number, because 381221 - 2¹⁰ = 380197 is a prime.

Together with 381223, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 381221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (381223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 190610 + 190611.

It is an arithmetic number, because the mean of its divisors is an integer number (190611).

2³⁸¹²²¹ is an apocalyptic number.

It is an amenable number.

381221 is a deficient number, since it is larger than the sum of its proper divisors (1).

381221 is an equidigital number, since it uses as much as digits as its factorization.

381221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96, while the sum is 17.

The square root of 381221 is about 617.4309678013. The cubic root of 381221 is about 72.5090595100.

The spelling of 381221 in words is "three hundred eighty-one thousand, two hundred twenty-one".