251125322221 has 4 divisors (see below), whose sum is σ = 255242130844. Its totient is φ = 247008513600.

The previous prime is 251125322207. The next prime is 251125322291. The reversal of 251125322221 is 122223521152.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 108233762121 + 142891560100 = 328989^2 + 378010^2 .

It is a cyclic number.

It is not a de Polignac number, because 251125322221 - 2⁷ = 251125322093 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 251125322221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251125322291) 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, 2058404220 + ... + 2058404341.

It is an arithmetic number, because the mean of its divisors is an integer number (63810532711).

Almost surely, 2^251125322221 is an apocalyptic number.

It is an amenable number.

251125322221 is a deficient number, since it is larger than the sum of its proper divisors (4116808623).

251125322221 is an equidigital number, since it uses as much as digits as its factorization.

251125322221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4116808622.

The product of its digits is 4800, while the sum is 28.

Adding to 251125322221 its reverse (122223521152), we get a palindrome (373348843373).

The spelling of 251125322221 in words is "two hundred fifty-one billion, one hundred twenty-five million, three hundred twenty-two thousand, two hundred twenty-one".