85721334217 has 2 divisors, whose sum is σ = 85721334218. Its totient is φ = 85721334216.

The previous prime is 85721334161. The next prime is 85721334239. The reversal of 85721334217 is 71243312758.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 55272480201 + 30448854016 = 235101^2 + 174496^2 .

It is a cyclic number.

It is not a de Polignac number, because 85721334217 - 2¹⁹ = 85720809929 is a prime.

It is not a weakly prime, because it can be changed into another prime (85721334247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 42860667108 + 42860667109.

It is an arithmetic number, because the mean of its divisors is an integer number (42860667109).

Almost surely, 2^85721334217 is an apocalyptic number.

It is an amenable number.

85721334217 is a deficient number, since it is larger than the sum of its proper divisors (1).

85721334217 is an equidigital number, since it uses as much as digits as its factorization.

85721334217 is an evil number, because the sum of its binary digits is even.

The product of its digits is 282240, while the sum is 43.

The spelling of 85721334217 in words is "eighty-five billion, seven hundred twenty-one million, three hundred thirty-four thousand, two hundred seventeen".