821388013 has 2 divisors, whose sum is σ = 821388014. Its totient is φ = 821388012.

The previous prime is 821387999. The next prime is 821388019. The reversal of 821388013 is 310883128.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 649332324 + 172055689 = 25482^2 + 13117^2 .

It is a cyclic number.

It is not a de Polignac number, because 821388013 - 2⁵ = 821387981 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 821388013.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (821388019) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410694006 + 410694007.

It is an arithmetic number, because the mean of its divisors is an integer number (410694007).

Almost surely, 2^821388013 is an apocalyptic number.

It is an amenable number.

821388013 is a deficient number, since it is larger than the sum of its proper divisors (1).

821388013 is an equidigital number, since it uses as much as digits as its factorization.

821388013 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9216, while the sum is 34.

The square root of 821388013 is about 28659.8676375171. The cubic root of 821388013 is about 936.5179810821.

The spelling of 821388013 in words is "eight hundred twenty-one million, three hundred eighty-eight thousand, thirteen".