251278321345 has 8 divisors (see below), whose sum is σ = 308888473320. Its totient is φ = 196119665280.

The previous prime is 251278321321. The next prime is 251278321351. The reversal of 251278321345 is 543123872152.

It can be written as a sum of positive squares in 4 ways, for example, as 21162393729 + 230115927616 = 145473^2 + 479704^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 251278321345 - 2¹¹ = 251278319297 is a prime.

It is a super-2 number, since 2×251278321345² (a number of 24 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 612873750 + ... + 612874159.

It is an arithmetic number, because the mean of its divisors is an integer number (38611059165).

Almost surely, 2^251278321345 is an apocalyptic number.

It is an amenable number.

251278321345 is a deficient number, since it is larger than the sum of its proper divisors (57610151975).

251278321345 is a wasteful number, since it uses less digits than its factorization.

251278321345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1225747955.

The product of its digits is 403200, while the sum is 43.

The spelling of 251278321345 in words is "two hundred fifty-one billion, two hundred seventy-eight million, three hundred twenty-one thousand, three hundred forty-five".