1261251113 has 2 divisors, whose sum is σ = 1261251114. Its totient is φ = 1261251112.

The previous prime is 1261251109. The next prime is 1261251127. The reversal of 1261251113 is 3111521621.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1116361744 + 144889369 = 33412^2 + 12037^2 .

It is a cyclic number.

It is not a de Polignac number, because 1261251113 - 2² = 1261251109 is a prime.

It is not a weakly prime, because it can be changed into another prime (1261251193) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 630625556 + 630625557.

It is an arithmetic number, because the mean of its divisors is an integer number (630625557).

Almost surely, 2^1261251113 is an apocalyptic number.

It is an amenable number.

1261251113 is a deficient number, since it is larger than the sum of its proper divisors (1).

1261251113 is an equidigital number, since it uses as much as digits as its factorization.

1261251113 is an evil number, because the sum of its binary digits is even.

The product of its digits is 360, while the sum is 23.

The square root of 1261251113 is about 35514.0973839967. The cubic root of 1261251113 is about 1080.4396680947.

Adding to 1261251113 its reverse (3111521621), we get a palindrome (4372772734).

The spelling of 1261251113 in words is "one billion, two hundred sixty-one million, two hundred fifty-one thousand, one hundred thirteen".