20513540415391 has 2 divisors, whose sum is σ = 20513540415392. Its totient is φ = 20513540415390.

The previous prime is 20513540415341. The next prime is 20513540415419. The reversal of 20513540415391 is 19351404531502.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20513540415391 - 2¹⁷ = 20513540284319 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20513540415331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10256770207695 + 10256770207696.

It is an arithmetic number, because the mean of its divisors is an integer number (10256770207696).

Almost surely, 2^{20513540415391} is an apocalyptic number.

20513540415391 is a deficient number, since it is larger than the sum of its proper divisors (1).

20513540415391 is an equidigital number, since it uses as much as digits as its factorization.

20513540415391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 324000, while the sum is 43.

Adding to 20513540415391 its reverse (19351404531502), we get a palindrome (39864944946893).

The spelling of 20513540415391 in words is "twenty trillion, five hundred thirteen billion, five hundred forty million, four hundred fifteen thousand, three hundred ninety-one".