20505204413 has 2 divisors, whose sum is σ = 20505204414. Its totient is φ = 20505204412.

The previous prime is 20505204367. The next prime is 20505204443. The reversal of 20505204413 is 31440250502.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10576476964 + 9928727449 = 102842^2 + 99643^2 .

It is a cyclic number.

It is not a de Polignac number, because 20505204413 - 2¹⁴ = 20505188029 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20505204443) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10252602206 + 10252602207.

It is an arithmetic number, because the mean of its divisors is an integer number (10252602207).

Almost surely, 2^20505204413 is an apocalyptic number.

It is an amenable number.

20505204413 is a deficient number, since it is larger than the sum of its proper divisors (1).

20505204413 is an equidigital number, since it uses as much as digits as its factorization.

20505204413 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4800, while the sum is 26.

Adding to 20505204413 its reverse (31440250502), we get a palindrome (51945454915).

The spelling of 20505204413 in words is "twenty billion, five hundred five million, two hundred four thousand, four hundred thirteen".