1261217141 has 2 divisors, whose sum is σ = 1261217142. Its totient is φ = 1261217140.

The previous prime is 1261217137. The next prime is 1261217147. The reversal of 1261217141 is 1417121621.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1151177041 + 110040100 = 33929^2 + 10490^2 .

It is an emirp because it is prime and its reverse (1417121621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1261217141 - 2² = 1261217137 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1261217141.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1261217147) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 630608570 + 630608571.

It is an arithmetic number, because the mean of its divisors is an integer number (630608571).

Almost surely, 2^1261217141 is an apocalyptic number.

It is an amenable number.

1261217141 is a deficient number, since it is larger than the sum of its proper divisors (1).

1261217141 is an equidigital number, since it uses as much as digits as its factorization.

1261217141 is an evil number, because the sum of its binary digits is even.

The product of its digits is 672, while the sum is 26.

The square root of 1261217141 is about 35513.6190918357. The cubic root of 1261217141 is about 1080.4299674026.

Adding to 1261217141 its reverse (1417121621), we get a palindrome (2678338762).

The spelling of 1261217141 in words is "one billion, two hundred sixty-one million, two hundred seventeen thousand, one hundred forty-one".