20515013 has 2 divisors, whose sum is σ = 20515014. Its totient is φ = 20515012.

The previous prime is 20515009. The next prime is 20515051. The reversal of 20515013 is 31051502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20268004 + 247009 = 4502^2 + 497^2 .

It is a cyclic number.

It is not a de Polignac number, because 20515013 - 2² = 20515009 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20514982 and 20515000.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20515813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10257506 + 10257507.

It is an arithmetic number, because the mean of its divisors is an integer number (10257507).

Almost surely, 2^20515013 is an apocalyptic number.

It is an amenable number.

20515013 is a deficient number, since it is larger than the sum of its proper divisors (1).

20515013 is an equidigital number, since it uses as much as digits as its factorization.

20515013 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 150, while the sum is 17.

The square root of 20515013 is about 4529.3501741420. The cubic root of 20515013 is about 273.7519777732.

Adding to 20515013 its reverse (31051502), we get a palindrome (51566515).

The spelling of 20515013 in words is "twenty million, five hundred fifteen thousand, thirteen".