30881813 has 2 divisors, whose sum is σ = 30881814. Its totient is φ = 30881812.

The previous prime is 30881803. The next prime is 30881827. The reversal of 30881813 is 31818803.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30547729 + 334084 = 5527^2 + 578^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-30881813 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 30881813.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (30881803) 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, 15440906 + 15440907.

It is an arithmetic number, because the mean of its divisors is an integer number (15440907).

Almost surely, 2^30881813 is an apocalyptic number.

It is an amenable number.

30881813 is a deficient number, since it is larger than the sum of its proper divisors (1).

30881813 is an equidigital number, since it uses as much as digits as its factorization.

30881813 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 30881813 is about 5557.1407216301. The cubic root of 30881813 is about 313.7383413920.

The spelling of 30881813 in words is "thirty million, eight hundred eighty-one thousand, eight hundred thirteen".