251424121 has 4 divisors (see below), whose sum is σ = 270764452. Its totient is φ = 232083792.

The previous prime is 251424091. The next prime is 251424163. The reversal of 251424121 is 121424152.

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 22325625 + 229098496 = 4725^2 + 15136^2 .

It is a cyclic number.

It is not a de Polignac number, because 251424121 - 2¹⁵ = 251391353 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 251424092 and 251424101.

It is not an unprimeable number, because it can be changed into a prime (251424221) 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 in 3 ways as a sum of consecutive naturals, for example, 9670146 + ... + 9670171.

It is an arithmetic number, because the mean of its divisors is an integer number (67691113).

Almost surely, 2^251424121 is an apocalyptic number.

It is an amenable number.

251424121 is a deficient number, since it is larger than the sum of its proper divisors (19340331).

251424121 is a wasteful number, since it uses less digits than its factorization.

251424121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19340330.

The product of its digits is 640, while the sum is 22.

The square root of 251424121 is about 15856.3590082970. The cubic root of 251424121 is about 631.1544474393.

Adding to 251424121 its reverse (121424152), we get a palindrome (372848273).

The spelling of 251424121 in words is "two hundred fifty-one million, four hundred twenty-four thousand, one hundred twenty-one".