65721857 has 2 divisors, whose sum is σ = 65721858. Its totient is φ = 65721856.

The previous prime is 65721809. The next prime is 65721863. The reversal of 65721857 is 75812756.

65721857 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 41357761 + 24364096 = 6431^2 + 4936^2 .

It is a cyclic number.

It is not a de Polignac number, because 65721857 - 2¹⁰ = 65720833 is a prime.

It is not a weakly prime, because it can be changed into another prime (65720857) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32860928 + 32860929.

It is an arithmetic number, because the mean of its divisors is an integer number (32860929).

Almost surely, 2^65721857 is an apocalyptic number.

It is an amenable number.

65721857 is a deficient number, since it is larger than the sum of its proper divisors (1).

65721857 is an equidigital number, since it uses as much as digits as its factorization.

65721857 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 117600, while the sum is 41.

The square root of 65721857 is about 8106.9018126532. The cubic root of 65721857 is about 403.5555044140. Note that the first 4 decimals are identical.

The spelling of 65721857 in words is "sixty-five million, seven hundred twenty-one thousand, eight hundred fifty-seven".