30819221 has 2 divisors, whose sum is σ = 30819222. Its totient is φ = 30819220.

The previous prime is 30819209. The next prime is 30819223. The reversal of 30819221 is 12291803.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23902321 + 6916900 = 4889^2 + 2630^2 .

It is a cyclic number.

It is not a de Polignac number, because 30819221 - 2¹⁰ = 30818197 is a prime.

It is a Sophie Germain prime.

Together with 30819223, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (30819223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15409610 + 15409611.

It is an arithmetic number, because the mean of its divisors is an integer number (15409611).

Almost surely, 2^30819221 is an apocalyptic number.

It is an amenable number.

30819221 is a deficient number, since it is larger than the sum of its proper divisors (1).

30819221 is an equidigital number, since it uses as much as digits as its factorization.

30819221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 30819221 is about 5551.5061920167. The cubic root of 30819221 is about 313.5262338917.

The spelling of 30819221 in words is "thirty million, eight hundred nineteen thousand, two hundred twenty-one".