515056781 has 2 divisors, whose sum is σ = 515056782. Its totient is φ = 515056780.

The previous prime is 515056757. The next prime is 515056783. The reversal of 515056781 is 187650515.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 373803556 + 141253225 = 19334^2 + 11885^2 .

It is a cyclic number.

It is not a de Polignac number, because 515056781 - 2¹⁴ = 515040397 is a prime.

It is a super-2 number, since 2×515056781² = 530566975308163922, which contains 22 as substring.

Together with 515056783, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (515056783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 257528390 + 257528391.

It is an arithmetic number, because the mean of its divisors is an integer number (257528391).

Almost surely, 2^515056781 is an apocalyptic number.

It is an amenable number.

515056781 is a deficient number, since it is larger than the sum of its proper divisors (1).

515056781 is an equidigital number, since it uses as much as digits as its factorization.

515056781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 42000, while the sum is 38.

The square root of 515056781 is about 22694.8624362431. The cubic root of 515056781 is about 801.5889155325.

The spelling of 515056781 in words is "five hundred fifteen million, fifty-six thousand, seven hundred eighty-one".