51689857 has 2 divisors, whose sum is σ = 51689858. Its totient is φ = 51689856.

The previous prime is 51689831. The next prime is 51689863. The reversal of 51689857 is 75898615.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 39828721 + 11861136 = 6311^2 + 3444^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51689857 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 51689857.

It is not a weakly prime, because it can be changed into another prime (51689887) 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, 25844928 + 25844929.

It is an arithmetic number, because the mean of its divisors is an integer number (25844929).

Almost surely, 2^51689857 is an apocalyptic number.

It is an amenable number.

51689857 is a deficient number, since it is larger than the sum of its proper divisors (1).

51689857 is an equidigital number, since it uses as much as digits as its factorization.

51689857 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 604800, while the sum is 49.

The square root of 51689857 is about 7189.5658422467. The cubic root of 51689857 is about 372.5075763815.

The spelling of 51689857 in words is "fifty-one million, six hundred eighty-nine thousand, eight hundred fifty-seven".