261734909 has 2 divisors, whose sum is σ = 261734910. Its totient is φ = 261734908.

The previous prime is 261734887. The next prime is 261734911. The reversal of 261734909 is 909437162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 261727684 + 7225 = 16178^2 + 85^2 .

It is a cyclic number.

It is not a de Polignac number, because 261734909 - 2⁸ = 261734653 is a prime.

It is a Sophie Germain prime.

Together with 261734911, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261734959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130867454 + 130867455.

It is an arithmetic number, because the mean of its divisors is an integer number (130867455).

Almost surely, 2^261734909 is an apocalyptic number.

It is an amenable number.

261734909 is a deficient number, since it is larger than the sum of its proper divisors (1).

261734909 is an equidigital number, since it uses as much as digits as its factorization.

261734909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 81648, while the sum is 41.

The square root of 261734909 is about 16178.2232955291. The cubic root of 261734909 is about 639.6669075617. Note that the first 3 decimals are identical.

The spelling of 261734909 in words is "two hundred sixty-one million, seven hundred thirty-four thousand, nine hundred nine".