261645347 has 2 divisors, whose sum is σ = 261645348. Its totient is φ = 261645346.

The previous prime is 261645343. The next prime is 261645379. The reversal of 261645347 is 743546162.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 261645347 - 2² = 261645343 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261645347.

It is not a weakly prime, because it can be changed into another prime (261645343) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130822673 + 130822674.

It is an arithmetic number, because the mean of its divisors is an integer number (130822674).

Almost surely, 2^261645347 is an apocalyptic number.

261645347 is a deficient number, since it is larger than the sum of its proper divisors (1).

261645347 is an equidigital number, since it uses as much as digits as its factorization.

261645347 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 120960, while the sum is 38.

The square root of 261645347 is about 16175.4550786060. The cubic root of 261645347 is about 639.5939375688.

The spelling of 261645347 in words is "two hundred sixty-one million, six hundred forty-five thousand, three hundred forty-seven".