20512107810721 has 2 divisors, whose sum is σ = 20512107810722. Its totient is φ = 20512107810720.

The previous prime is 20512107810679. The next prime is 20512107810757. The reversal of 20512107810721 is 12701870121502.

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., 11555920360000 + 8956187450721 = 3399400^2 + 2992689^2 .

It is a cyclic number.

It is not a de Polignac number, because 20512107810721 - 2¹⁷ = 20512107679649 is a prime.

It is not a weakly prime, because it can be changed into another prime (20512107870721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10256053905360 + 10256053905361.

It is an arithmetic number, because the mean of its divisors is an integer number (10256053905361).

Almost surely, 2^{20512107810721} is an apocalyptic number.

It is an amenable number.

20512107810721 is a deficient number, since it is larger than the sum of its proper divisors (1).

20512107810721 is an equidigital number, since it uses as much as digits as its factorization.

20512107810721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15680, while the sum is 37.

The spelling of 20512107810721 in words is "twenty trillion, five hundred twelve billion, one hundred seven million, eight hundred ten thousand, seven hundred twenty-one".