10391221 has 2 divisors, whose sum is σ = 10391222. Its totient is φ = 10391220.

The previous prime is 10391219. The next prime is 10391279. The reversal of 10391221 is 12219301.

10391221 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8346321 + 2044900 = 2889^2 + 1430^2 .

It is a cyclic number.

It is not a de Polignac number, because 10391221 - 2¹ = 10391219 is a prime.

Together with 10391219, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (10391321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5195610 + 5195611.

It is an arithmetic number, because the mean of its divisors is an integer number (5195611).

Almost surely, 2^10391221 is an apocalyptic number.

It is an amenable number.

10391221 is a deficient number, since it is larger than the sum of its proper divisors (1).

10391221 is an equidigital number, since it uses as much as digits as its factorization.

10391221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108, while the sum is 19.

The square root of 10391221 is about 3223.5416857860. The cubic root of 10391221 is about 218.2171404881.

The spelling of 10391221 in words is "ten million, three hundred ninety-one thousand, two hundred twenty-one".