261589943 has 2 divisors, whose sum is σ = 261589944. Its totient is φ = 261589942.

The previous prime is 261589903. The next prime is 261589981. The reversal of 261589943 is 349985162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261589943 - 2²² = 257395639 is a prime.

It is a super-3 number, since 3×261589943³ (a number of 26 digits) contains 333 as substring.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261589903) 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, 130794971 + 130794972.

It is an arithmetic number, because the mean of its divisors is an integer number (130794972).

Almost surely, 2^261589943 is an apocalyptic number.

261589943 is a deficient number, since it is larger than the sum of its proper divisors (1).

261589943 is an equidigital number, since it uses as much as digits as its factorization.

261589943 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 466560, while the sum is 47.

The square root of 261589943 is about 16173.7423931507. The cubic root of 261589943 is about 639.5487892227.

The spelling of 261589943 in words is "two hundred sixty-one million, five hundred eighty-nine thousand, nine hundred forty-three".