247943561 has 2 divisors, whose sum is σ = 247943562. Its totient is φ = 247943560.

The previous prime is 247943539. The next prime is 247943581. The reversal of 247943561 is 165349742.

247943561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 152275600 + 95667961 = 12340^2 + 9781^2 .

It is a cyclic number.

It is not a de Polignac number, because 247943561 - 2¹⁰ = 247942537 is a prime.

It is a super-2 number, since 2×247943561² = 122952018882721442, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (247943581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 123971780 + 123971781.

It is an arithmetic number, because the mean of its divisors is an integer number (123971781).

Almost surely, 2^247943561 is an apocalyptic number.

It is an amenable number.

247943561 is a deficient number, since it is larger than the sum of its proper divisors (1).

247943561 is an equidigital number, since it uses as much as digits as its factorization.

247943561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 181440, while the sum is 41.

The square root of 247943561 is about 15746.2237060192. The cubic root of 247943561 is about 628.2284665444.

The spelling of 247943561 in words is "two hundred forty-seven million, nine hundred forty-three thousand, five hundred sixty-one".