20355102513521 has 2 divisors, whose sum is σ = 20355102513522. Its totient is φ = 20355102513520.

The previous prime is 20355102513437. The next prime is 20355102513547. The reversal of 20355102513521 is 12531520155302.

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., 11221796511025 + 9133306002496 = 3349895^2 + 3022136^2 .

It is a cyclic number.

It is not a de Polignac number, because 20355102513521 - 2¹⁰ = 20355102512497 is a prime.

It is not a weakly prime, because it can be changed into another prime (20355102516521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10177551256760 + 10177551256761.

It is an arithmetic number, because the mean of its divisors is an integer number (10177551256761).

Almost surely, 2^{20355102513521} is an apocalyptic number.

It is an amenable number.

20355102513521 is a deficient number, since it is larger than the sum of its proper divisors (1).

20355102513521 is an equidigital number, since it uses as much as digits as its factorization.

20355102513521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 45000, while the sum is 35.

Adding to 20355102513521 its reverse (12531520155302), we get a palindrome (32886622668823).

The spelling of 20355102513521 in words is "twenty trillion, three hundred fifty-five billion, one hundred two million, five hundred thirteen thousand, five hundred twenty-one".