1251543121327 has 4 divisors (see below), whose sum is σ = 1258534982520. Its totient is φ = 1244551260136.

The previous prime is 1251543121249. The next prime is 1251543121349. The reversal of 1251543121327 is 7231213451521.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1251543121327 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 (1251543121027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3495930328 + ... + 3495930685.

It is an arithmetic number, because the mean of its divisors is an integer number (314633745630).

Almost surely, 2^{1251543121327} is an apocalyptic number.

1251543121327 is a deficient number, since it is larger than the sum of its proper divisors (6991861193).

1251543121327 is an equidigital number, since it uses as much as digits as its factorization.

1251543121327 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6991861192.

The product of its digits is 50400, while the sum is 37.

Adding to 1251543121327 its reverse (7231213451521), we get a palindrome (8482756572848).

The spelling of 1251543121327 in words is "one trillion, two hundred fifty-one billion, five hundred forty-three million, one hundred twenty-one thousand, three hundred twenty-seven".