813109862561 has 2 divisors, whose sum is σ = 813109862562. Its totient is φ = 813109862560.

The previous prime is 813109862533. The next prime is 813109862573. The reversal of 813109862561 is 165268901318.

813109862561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 661034041600 + 152075820961 = 813040^2 + 389969^2 .

It is a cyclic number.

It is not a de Polignac number, because 813109862561 - 2¹⁴ = 813109846177 is a prime.

It is a super-2 number, since 2×813109862561² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (813109862581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 406554931280 + 406554931281.

It is an arithmetic number, because the mean of its divisors is an integer number (406554931281).

Almost surely, 2^813109862561 is an apocalyptic number.

It is an amenable number.

813109862561 is a deficient number, since it is larger than the sum of its proper divisors (1).

813109862561 is an equidigital number, since it uses as much as digits as its factorization.

813109862561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 622080, while the sum is 50.

The spelling of 813109862561 in words is "eight hundred thirteen billion, one hundred nine million, eight hundred sixty-two thousand, five hundred sixty-one".