261562256489 has 4 divisors (see below), whose sum is σ = 261885572820. Its totient is φ = 261238940160.

The previous prime is 261562256477. The next prime is 261562256539. The reversal of 261562256489 is 984652265162.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 232092697600 + 29469558889 = 481760^2 + 171667^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261562256489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261562256419) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 161656952 + ... + 161658569.

It is an arithmetic number, because the mean of its divisors is an integer number (65471393205).

Almost surely, 2^261562256489 is an apocalyptic number.

It is an amenable number.

261562256489 is a deficient number, since it is larger than the sum of its proper divisors (323316331).

261562256489 is an equidigital number, since it uses as much as digits as its factorization.

261562256489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 323316330.

The product of its digits is 12441600, while the sum is 56.

The spelling of 261562256489 in words is "two hundred sixty-one billion, five hundred sixty-two million, two hundred fifty-six thousand, four hundred eighty-nine".