1251561134213 has 16 divisors (see below), whose sum is σ = 1427160772800. Its totient is φ = 1087297671936.

The previous prime is 1251561134209. The next prime is 1251561134251. The reversal of 1251561134213 is 3124311651521.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1251561134213 - 2² = 1251561134209 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1251561136213) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10892738 + ... + 11007036.

It is an arithmetic number, because the mean of its divisors is an integer number (89197548300).

Almost surely, 2^{1251561134213} is an apocalyptic number.

1251561134213 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

1251561134213 is a deficient number, since it is larger than the sum of its proper divisors (175599638587).

1251561134213 is a wasteful number, since it uses less digits than its factorization.

1251561134213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163876.

The product of its digits is 21600, while the sum is 35.

Adding to 1251561134213 its reverse (3124311651521), we get a palindrome (4375872785734).

The spelling of 1251561134213 in words is "one trillion, two hundred fifty-one billion, five hundred sixty-one million, one hundred thirty-four thousand, two hundred thirteen".