1251221113 has 2 divisors, whose sum is σ = 1251221114. Its totient is φ = 1251221112.

The previous prime is 1251221107. The next prime is 1251221129. The reversal of 1251221113 is 3111221521.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 800210944 + 451010169 = 28288^2 + 21237^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1251221113 is a prime.

It is not a weakly prime, because it can be changed into another prime (1251224113) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 625610556 + 625610557.

It is an arithmetic number, because the mean of its divisors is an integer number (625610557).

Almost surely, 2^1251221113 is an apocalyptic number.

It is an amenable number.

1251221113 is a deficient number, since it is larger than the sum of its proper divisors (1).

1251221113 is an equidigital number, since it uses as much as digits as its factorization.

1251221113 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 120, while the sum is 19.

The square root of 1251221113 is about 35372.6039895284. The cubic root of 1251221113 is about 1077.5680052829.

Adding to 1251221113 its reverse (3111221521), we get a palindrome (4362442634).

The spelling of 1251221113 in words is "one billion, two hundred fifty-one million, two hundred twenty-one thousand, one hundred thirteen".