261943247 has 2 divisors, whose sum is σ = 261943248. Its totient is φ = 261943246.

The previous prime is 261943243. The next prime is 261943289. The reversal of 261943247 is 742349162.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 261943247 - 2² = 261943243 is a prime.

It is a super-2 number, since 2×261943247² = 137228529297806018, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261943247.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261943243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130971623 + 130971624.

It is an arithmetic number, because the mean of its divisors is an integer number (130971624).

Almost surely, 2^261943247 is an apocalyptic number.

261943247 is a deficient number, since it is larger than the sum of its proper divisors (1).

261943247 is an equidigital number, since it uses as much as digits as its factorization.

261943247 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72576, while the sum is 38.

The square root of 261943247 is about 16184.6608552666. The cubic root of 261943247 is about 639.8365850682.

The spelling of 261943247 in words is "two hundred sixty-one million, nine hundred forty-three thousand, two hundred forty-seven".