1251801810001 has 2 divisors, whose sum is σ = 1251801810002. Its totient is φ = 1251801810000.

The previous prime is 1251801809977. The next prime is 1251801810037. The reversal of 1251801810001 is 1000181081521.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1001800810000 + 250001000001 = 1000900^2 + 500001^2 .

It is a cyclic number.

It is not a de Polignac number, because 1251801810001 - 2⁵ = 1251801809969 is a prime.

It is not a weakly prime, because it can be changed into another prime (1251801810071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 625900905000 + 625900905001.

It is an arithmetic number, because the mean of its divisors is an integer number (625900905001).

Almost surely, 2^{1251801810001} is an apocalyptic number.

It is an amenable number.

1251801810001 is a deficient number, since it is larger than the sum of its proper divisors (1).

1251801810001 is an equidigital number, since it uses as much as digits as its factorization.

1251801810001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 640, while the sum is 28.

Adding to 1251801810001 its reverse (1000181081521), we get a palindrome (2251982891522).

The spelling of 1251801810001 in words is "one trillion, two hundred fifty-one billion, eight hundred one million, eight hundred ten thousand, one".