263843123561 has 2 divisors, whose sum is σ = 263843123562. Its totient is φ = 263843123560.

The previous prime is 263843123483. The next prime is 263843123567. The reversal of 263843123561 is 165321348362.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 212594766400 + 51248357161 = 461080^2 + 226381^2 .

It is a cyclic number.

It is not a de Polignac number, because 263843123561 - 2¹⁸ = 263842861417 is a prime.

It is a super-2 number, since 2×263843123561² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (263843123567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 131921561780 + 131921561781.

It is an arithmetic number, because the mean of its divisors is an integer number (131921561781).

Almost surely, 2^263843123561 is an apocalyptic number.

It is an amenable number.

263843123561 is a deficient number, since it is larger than the sum of its proper divisors (1).

263843123561 is an equidigital number, since it uses as much as digits as its factorization.

263843123561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 622080, while the sum is 44.

The spelling of 263843123561 in words is "two hundred sixty-three billion, eight hundred forty-three million, one hundred twenty-three thousand, five hundred sixty-one".