51561317 has 2 divisors, whose sum is σ = 51561318. Its totient is φ = 51561316.

The previous prime is 51561311. The next prime is 51561319. The reversal of 51561317 is 71316515.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 40972801 + 10588516 = 6401^2 + 3254^2 .

It is a cyclic number.

It is not a de Polignac number, because 51561317 - 2⁶ = 51561253 is a prime.

Together with 51561319, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 51561317.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51561311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25780658 + 25780659.

It is an arithmetic number, because the mean of its divisors is an integer number (25780659).

Almost surely, 2^51561317 is an apocalyptic number.

It is an amenable number.

51561317 is a deficient number, since it is larger than the sum of its proper divisors (1).

51561317 is an equidigital number, since it uses as much as digits as its factorization.

51561317 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3150, while the sum is 29.

The square root of 51561317 is about 7180.6209341533. The cubic root of 51561317 is about 372.1985417408.

The spelling of 51561317 in words is "fifty-one million, five hundred sixty-one thousand, three hundred seventeen".