20345032402561 has 2 divisors, whose sum is σ = 20345032402562. Its totient is φ = 20345032402560.

The previous prime is 20345032402553. The next prime is 20345032402571. The reversal of 20345032402561 is 16520423054302.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10928849186161 + 9416183216400 = 3305881^2 + 3068580^2 .

It is a cyclic number.

It is not a de Polignac number, because 20345032402561 - 2³ = 20345032402553 is a prime.

It is a super-2 number, since 2×20345032402561² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20345032402561.

It is not a weakly prime, because it can be changed into another prime (20345032402571) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10172516201280 + 10172516201281.

It is an arithmetic number, because the mean of its divisors is an integer number (10172516201281).

Almost surely, 2^{20345032402561} is an apocalyptic number.

It is an amenable number.

20345032402561 is a deficient number, since it is larger than the sum of its proper divisors (1).

20345032402561 is an equidigital number, since it uses as much as digits as its factorization.

20345032402561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 172800, while the sum is 37.

Adding to 20345032402561 its reverse (16520423054302), we get a palindrome (36865455456863).

The spelling of 20345032402561 in words is "twenty trillion, three hundred forty-five billion, thirty-two million, four hundred two thousand, five hundred sixty-one".