251266321 has 2 divisors, whose sum is σ = 251266322. Its totient is φ = 251266320.

The previous prime is 251266319. The next prime is 251266331. The reversal of 251266321 is 123662152.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 157854096 + 93412225 = 12564^2 + 9665^2 .

It is a cyclic number.

It is not a de Polignac number, because 251266321 - 2¹ = 251266319 is a prime.

Together with 251266319, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 251266321.

It is not a weakly prime, because it can be changed into another prime (251266331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125633160 + 125633161.

It is an arithmetic number, because the mean of its divisors is an integer number (125633161).

Almost surely, 2^251266321 is an apocalyptic number.

It is an amenable number.

251266321 is a deficient number, since it is larger than the sum of its proper divisors (1).

251266321 is an equidigital number, since it uses as much as digits as its factorization.

251266321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4320, while the sum is 28.

The square root of 251266321 is about 15851.3823056540. The cubic root of 251266321 is about 631.0223770887.

The spelling of 251266321 in words is "two hundred fifty-one million, two hundred sixty-six thousand, three hundred twenty-one".