1261217543 has 2 divisors, whose sum is σ = 1261217544. Its totient is φ = 1261217542.

The previous prime is 1261217509. The next prime is 1261217653. The reversal of 1261217543 is 3457121621.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1261217543 - 2³⁰ = 187475719 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1261216543) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 630608771 + 630608772.

It is an arithmetic number, because the mean of its divisors is an integer number (630608772).

Almost surely, 2^1261217543 is an apocalyptic number.

1261217543 is a deficient number, since it is larger than the sum of its proper divisors (1).

1261217543 is an equidigital number, since it uses as much as digits as its factorization.

1261217543 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10080, while the sum is 32.

The square root of 1261217543 is about 35513.6247516358. The cubic root of 1261217543 is about 1080.4300821946.

The spelling of 1261217543 in words is "one billion, two hundred sixty-one million, two hundred seventeen thousand, five hundred forty-three".