215929806817 has 2 divisors, whose sum is σ = 215929806818. Its totient is φ = 215929806816.

The previous prime is 215929806767. The next prime is 215929806853. The reversal of 215929806817 is 718608929512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 202033169361 + 13896637456 = 449481^2 + 117884^2 .

It is a cyclic number.

It is not a de Polignac number, because 215929806817 - 2²⁷ = 215795589089 is a prime.

It is not a weakly prime, because it can be changed into another prime (215929806877) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107964903408 + 107964903409.

It is an arithmetic number, because the mean of its divisors is an integer number (107964903409).

Almost surely, 2^215929806817 is an apocalyptic number.

It is an amenable number.

215929806817 is a deficient number, since it is larger than the sum of its proper divisors (1).

215929806817 is an equidigital number, since it uses as much as digits as its factorization.

215929806817 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4354560, while the sum is 58.

The spelling of 215929806817 in words is "two hundred fifteen billion, nine hundred twenty-nine million, eight hundred six thousand, eight hundred seventeen".