261323399 has 2 divisors, whose sum is σ = 261323400. Its totient is φ = 261323398.

The previous prime is 261323369. The next prime is 261323423. The reversal of 261323399 is 993323162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261323399 - 2⁸ = 261323143 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261323339) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130661699 + 130661700.

It is an arithmetic number, because the mean of its divisors is an integer number (130661700).

Almost surely, 2^261323399 is an apocalyptic number.

261323399 is a deficient number, since it is larger than the sum of its proper divisors (1).

261323399 is an equidigital number, since it uses as much as digits as its factorization.

261323399 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 52488, while the sum is 38.

The square root of 261323399 is about 16165.5002706381. The cubic root of 261323399 is about 639.3314951605.

The spelling of 261323399 in words is "two hundred sixty-one million, three hundred twenty-three thousand, three hundred ninety-nine".