251320005 has 12 divisors (see below), whose sum is σ = 435621420. Its totient is φ = 134037312.

The previous prime is 251320001. The next prime is 251320009. The reversal of 251320005 is 500023152.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (251320001) and next prime (251320009).

It can be written as a sum of positive squares in 2 ways, for example, as 43441281 + 207878724 = 6591^2 + 14418^2 .

It is not a de Polignac number, because 251320005 - 2² = 251320001 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 251320005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251320001) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2792400 + ... + 2792489.

It is an arithmetic number, because the mean of its divisors is an integer number (36301785).

Almost surely, 2^251320005 is an apocalyptic number.

It is an amenable number.

251320005 is a deficient number, since it is larger than the sum of its proper divisors (184301415).

251320005 is a wasteful number, since it uses less digits than its factorization.

251320005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5584900 (or 5584897 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 18.

The square root of 251320005 is about 15853.0755691128. The cubic root of 251320005 is about 631.0673139946.

Adding to 251320005 its reverse (500023152), we get a palindrome (751343157).

The spelling of 251320005 in words is "two hundred fifty-one million, three hundred twenty thousand, five".