261569513969 has 2 divisors, whose sum is σ = 261569513970. Its totient is φ = 261569513968.

The previous prime is 261569513851. The next prime is 261569513981. The reversal of 261569513969 is 969315965162.

261569513969 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., 261473709025 + 95804944 = 511345^2 + 9788^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261569513969 is a prime.

It is a super-2 number, since 2×261569513969² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (261569513069) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130784756984 + 130784756985.

It is an arithmetic number, because the mean of its divisors is an integer number (130784756985).

Almost surely, 2^261569513969 is an apocalyptic number.

It is an amenable number.

261569513969 is a deficient number, since it is larger than the sum of its proper divisors (1).

261569513969 is an equidigital number, since it uses as much as digits as its factorization.

261569513969 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23619600, while the sum is 62.

The spelling of 261569513969 in words is "two hundred sixty-one billion, five hundred sixty-nine million, five hundred thirteen thousand, nine hundred sixty-nine".