51512281 has 2 divisors, whose sum is σ = 51512282. Its totient is φ = 51512280.

The previous prime is 51512267. The next prime is 51512299. The reversal of 51512281 is 18221515.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50993881 + 518400 = 7141^2 + 720^2 .

It is a cyclic number.

It is not a de Polignac number, because 51512281 - 2¹⁵ = 51479513 is a prime.

It is a super-2 number, since 2×51512281² = 5307030187645922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (51516281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25756140 + 25756141.

It is an arithmetic number, because the mean of its divisors is an integer number (25756141).

Almost surely, 2^51512281 is an apocalyptic number.

It is an amenable number.

51512281 is a deficient number, since it is larger than the sum of its proper divisors (1).

51512281 is an equidigital number, since it uses as much as digits as its factorization.

51512281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 800, while the sum is 25.

The square root of 51512281 is about 7177.2056540133. The cubic root of 51512281 is about 372.0805145222.

Adding to 51512281 its reverse (18221515), we get a palindrome (69733796).

The spelling of 51512281 in words is "fifty-one million, five hundred twelve thousand, two hundred eighty-one".