30391813 has 2 divisors, whose sum is σ = 30391814. Its totient is φ = 30391812.

The previous prime is 30391799. The next prime is 30391817. The reversal of 30391813 is 31819303.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28547649 + 1844164 = 5343^2 + 1358^2 .

It is an emirp because it is prime and its reverse (31819303) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-30391813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (30391817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15195906 + 15195907.

It is an arithmetic number, because the mean of its divisors is an integer number (15195907).

Almost surely, 2^30391813 is an apocalyptic number.

It is an amenable number.

30391813 is a deficient number, since it is larger than the sum of its proper divisors (1).

30391813 is an equidigital number, since it uses as much as digits as its factorization.

30391813 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 30391813 is about 5512.8770165858. The cubic root of 30391813 is about 312.0701306573.

The spelling of 30391813 in words is "thirty million, three hundred ninety-one thousand, eight hundred thirteen".