20315513 has 2 divisors, whose sum is σ = 20315514. Its totient is φ = 20315512.

The previous prime is 20315507. The next prime is 20315521. The reversal of 20315513 is 31551302.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14807104 + 5508409 = 3848^2 + 2347^2 .

It is a cyclic number.

It is not a de Polignac number, because 20315513 - 2⁴ = 20315497 is a prime.

It is not a weakly prime, because it can be changed into another prime (20315543) 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, 10157756 + 10157757.

It is an arithmetic number, because the mean of its divisors is an integer number (10157757).

Almost surely, 2^20315513 is an apocalyptic number.

It is an amenable number.

20315513 is a deficient number, since it is larger than the sum of its proper divisors (1).

20315513 is an equidigital number, since it uses as much as digits as its factorization.

20315513 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 450, while the sum is 20.

The square root of 20315513 is about 4507.2733442737. The cubic root of 20315513 is about 272.8617108337.

Adding to 20315513 its reverse (31551302), we get a palindrome (51866815).

The spelling of 20315513 in words is "twenty million, three hundred fifteen thousand, five hundred thirteen".