261822889 has 2 divisors, whose sum is σ = 261822890. Its totient is φ = 261822888.

The previous prime is 261822881. The next prime is 261822923. The reversal of 261822889 is 988228162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 216825625 + 44997264 = 14725^2 + 6708^2 .

It is a cyclic number.

It is not a de Polignac number, because 261822889 - 2³ = 261822881 is a prime.

It is not a weakly prime, because it can be changed into another prime (261822881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130911444 + 130911445.

It is an arithmetic number, because the mean of its divisors is an integer number (130911445).

Almost surely, 2^261822889 is an apocalyptic number.

It is an amenable number.

261822889 is a deficient number, since it is larger than the sum of its proper divisors (1).

261822889 is an equidigital number, since it uses as much as digits as its factorization.

261822889 is an evil number, because the sum of its binary digits is even.

The product of its digits is 221184, while the sum is 46.

The square root of 261822889 is about 16180.9421542752. The cubic root of 261822889 is about 639.7385724257.

The spelling of 261822889 in words is "two hundred sixty-one million, eight hundred twenty-two thousand, eight hundred eighty-nine".