251278321289 has 2 divisors, whose sum is σ = 251278321290. Its totient is φ = 251278321288.

The previous prime is 251278321279. The next prime is 251278321321. The reversal of 251278321289 is 982123872152.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 217466466889 + 33811854400 = 466333^2 + 183880^2 .

It is a cyclic number.

It is not a de Polignac number, because 251278321289 - 2³² = 246983353993 is a prime.

It is not a weakly prime, because it can be changed into another prime (251278321279) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 125639160644 + 125639160645.

It is an arithmetic number, because the mean of its divisors is an integer number (125639160645).

Almost surely, 2^251278321289 is an apocalyptic number.

It is an amenable number.

251278321289 is a deficient number, since it is larger than the sum of its proper divisors (1).

251278321289 is an equidigital number, since it uses as much as digits as its factorization.

251278321289 is an evil number, because the sum of its binary digits is even.

The product of its digits is 967680, while the sum is 50.

The spelling of 251278321289 in words is "two hundred fifty-one billion, two hundred seventy-eight million, three hundred twenty-one thousand, two hundred eighty-nine".