20306813 has 2 divisors, whose sum is σ = 20306814. Its totient is φ = 20306812.

The previous prime is 20306807. The next prime is 20306827. The reversal of 20306813 is 31860302.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20268004 + 38809 = 4502^2 + 197^2 .

It is a cyclic number.

It is not a de Polignac number, because 20306813 - 2⁶ = 20306749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20306113) 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, 10153406 + 10153407.

It is an arithmetic number, because the mean of its divisors is an integer number (10153407).

Almost surely, 2^20306813 is an apocalyptic number.

It is an amenable number.

20306813 is a deficient number, since it is larger than the sum of its proper divisors (1).

20306813 is an equidigital number, since it uses as much as digits as its factorization.

20306813 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 20306813 is about 4506.3081341604. The cubic root of 20306813 is about 272.8227547933.

The spelling of 20306813 in words is "twenty million, three hundred six thousand, eight hundred thirteen".