51856517 has 2 divisors, whose sum is σ = 51856518. Its totient is φ = 51856516.

The previous prime is 51856489. The next prime is 51856523. The reversal of 51856517 is 71565815.

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., 51854401 + 2116 = 7201^2 + 46^2 .

It is a cyclic number.

It is not a de Polignac number, because 51856517 - 2⁸ = 51856261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51850517) 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, 25928258 + 25928259.

It is an arithmetic number, because the mean of its divisors is an integer number (25928259).

Almost surely, 2^51856517 is an apocalyptic number.

It is an amenable number.

51856517 is a deficient number, since it is larger than the sum of its proper divisors (1).

51856517 is an equidigital number, since it uses as much as digits as its factorization.

51856517 is an odious number, because the sum of its binary digits is odd.

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

The square root of 51856517 is about 7201.1469225395. The cubic root of 51856517 is about 372.9074969410.

The spelling of 51856517 in words is "fifty-one million, eight hundred fifty-six thousand, five hundred seventeen".