30921239 has 2 divisors, whose sum is σ = 30921240. Its totient is φ = 30921238.

The previous prime is 30921211. The next prime is 30921271. The reversal of 30921239 is 93212903.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 30921239 - 2⁸ = 30920983 is a prime.

It is a super-2 number, since 2×30921239² = 1912246042590242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (30921299) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15460619 + 15460620.

It is an arithmetic number, because the mean of its divisors is an integer number (15460620).

Almost surely, 2^30921239 is an apocalyptic number.

30921239 is a deficient number, since it is larger than the sum of its proper divisors (1).

30921239 is an equidigital number, since it uses as much as digits as its factorization.

30921239 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2916, while the sum is 29.

The square root of 30921239 is about 5560.6869179985. The cubic root of 30921239 is about 313.8717984494.

The spelling of 30921239 in words is "thirty million, nine hundred twenty-one thousand, two hundred thirty-nine".