251221402112 has 90 divisors (see below), whose sum is σ = 533625127893. Its totient is φ = 118131105792.

The previous prime is 251221402093. The next prime is 251221402147. The reversal of 251221402112 is 211204122152.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

251221402112 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 229924086016 + 21297316096 = 479504^2 + 145936^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=354416.

It is a super-2 number, since 2×251221402112² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

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 in 8 ways as a sum of consecutive naturals, for example, 192801653 + ... + 192802955.

Almost surely, 2^251221402112 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 251221402112

251221402112 is an abundant number, since it is smaller than the sum of its proper divisors (282403725781).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

251221402112 is an frugal number, since it uses more digits than its factorization.

251221402112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2658 (or 1322 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 23.

Adding to 251221402112 its reverse (211204122152), we get a palindrome (462425524264).

The spelling of 251221402112 in words is "two hundred fifty-one billion, two hundred twenty-one million, four hundred two thousand, one hundred twelve".