30821321 has 2 divisors, whose sum is σ = 30821322. Its totient is φ = 30821320.

The previous prime is 30821317. The next prime is 30821327. The reversal of 30821321 is 12312803.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17131321 + 13690000 = 4139^2 + 3700^2 .

It is an emirp because it is prime and its reverse (12312803) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 30821321 - 2² = 30821317 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 30821293 and 30821302.

It is not a weakly prime, because it can be changed into another prime (30821327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15410660 + 15410661.

It is an arithmetic number, because the mean of its divisors is an integer number (15410661).

Almost surely, 2^30821321 is an apocalyptic number.

It is an amenable number.

30821321 is a deficient number, since it is larger than the sum of its proper divisors (1).

30821321 is an equidigital number, since it uses as much as digits as its factorization.

30821321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 30821321 is about 5551.6953266547. The cubic root of 30821321 is about 313.5333548822.

The spelling of 30821321 in words is "thirty million, eight hundred twenty-one thousand, three hundred twenty-one".