1251388887481 has 2 divisors, whose sum is σ = 1251388887482. Its totient is φ = 1251388887480.

The previous prime is 1251388887473. The next prime is 1251388887563. The reversal of 1251388887481 is 1847888831521.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1218504691881 + 32884195600 = 1103859^2 + 181340^2 .

It is a cyclic number.

It is not a de Polignac number, because 1251388887481 - 2³ = 1251388887473 is a prime.

It is a super-2 number, since 2×1251388887481² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1251388888481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 625694443740 + 625694443741.

It is an arithmetic number, because the mean of its divisors is an integer number (625694443741).

Almost surely, 2^{1251388887481} is an apocalyptic number.

It is an amenable number.

1251388887481 is a deficient number, since it is larger than the sum of its proper divisors (1).

1251388887481 is an equidigital number, since it uses as much as digits as its factorization.

1251388887481 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27525120, while the sum is 64.

The spelling of 1251388887481 in words is "one trillion, two hundred fifty-one billion, three hundred eighty-eight million, eight hundred eighty-seven thousand, four hundred eighty-one".