1251561134251 has 2 divisors, whose sum is σ = 1251561134252. Its totient is φ = 1251561134250.

The previous prime is 1251561134209. The next prime is 1251561134321. The reversal of 1251561134251 is 1524311651521.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1251561134251 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1251561134251.

It is not a weakly prime, because it can be changed into another prime (1251561134951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 625780567125 + 625780567126.

It is an arithmetic number, because the mean of its divisors is an integer number (625780567126).

Almost surely, 2^{1251561134251} is an apocalyptic number.

1251561134251 is a deficient number, since it is larger than the sum of its proper divisors (1).

1251561134251 is an equidigital number, since it uses as much as digits as its factorization.

1251561134251 is an evil number, because the sum of its binary digits is even.

The product of its digits is 36000, while the sum is 37.

Adding to 1251561134251 its reverse (1524311651521), we get a palindrome (2775872785772).

The spelling of 1251561134251 in words is "one trillion, two hundred fifty-one billion, five hundred sixty-one million, one hundred thirty-four thousand, two hundred fifty-one".