1251222221521 has 4 divisors (see below), whose sum is σ = 1251707382000. Its totient is φ = 1250737061044.

The previous prime is 1251222221503. The next prime is 1251222221531.

It is a happy number.

1251222221521 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1251222221521 - 2¹¹ = 1251222219473 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1251222221521.

It is not an unprimeable number, because it can be changed into a prime (1251222221531) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 242576371 + ... + 242581528.

It is an arithmetic number, because the mean of its divisors is an integer number (312926845500).

Almost surely, 2^{1251222221521} is an apocalyptic number.

It is an amenable number.

1251222221521 is a deficient number, since it is larger than the sum of its proper divisors (485160479).

1251222221521 is an equidigital number, since it uses as much as digits as its factorization.

1251222221521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 485160478.

The product of its digits is 3200, while the sum is 28.

The spelling of 1251222221521 in words is "one trillion, two hundred fifty-one billion, two hundred twenty-two million, two hundred twenty-one thousand, five hundred twenty-one".