20315445201521 has 2 divisors, whose sum is σ = 20315445201522. Its totient is φ = 20315445201520.

The previous prime is 20315445201481. The next prime is 20315445201539. The reversal of 20315445201521 is 12510254451302.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19282294927921 + 1033150273600 = 4391161^2 + 1016440^2 .

It is a cyclic number.

It is not a de Polignac number, because 20315445201521 - 2¹⁰ = 20315445200497 is a prime.

It is not a weakly prime, because it can be changed into another prime (20315445201421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10157722600760 + 10157722600761.

It is an arithmetic number, because the mean of its divisors is an integer number (10157722600761).

Almost surely, 2^{20315445201521} is an apocalyptic number.

It is an amenable number.

20315445201521 is a deficient number, since it is larger than the sum of its proper divisors (1).

20315445201521 is an equidigital number, since it uses as much as digits as its factorization.

20315445201521 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48000, while the sum is 35.

Adding to 20315445201521 its reverse (12510254451302), we get a palindrome (32825699652823).

The spelling of 20315445201521 in words is "twenty trillion, three hundred fifteen billion, four hundred forty-five million, two hundred one thousand, five hundred twenty-one".