215768904809 has 2 divisors, whose sum is σ = 215768904810. Its totient is φ = 215768904808.

The previous prime is 215768904773. The next prime is 215768904829. The reversal of 215768904809 is 908409867512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 189533976025 + 26234928784 = 435355^2 + 161972^2 .

It is a cyclic number.

It is not a de Polignac number, because 215768904809 - 2¹² = 215768900713 is a prime.

It is not a weakly prime, because it can be changed into another prime (215768904829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107884452404 + 107884452405.

It is an arithmetic number, because the mean of its divisors is an integer number (107884452405).

Almost surely, 2^215768904809 is an apocalyptic number.

It is an amenable number.

215768904809 is a deficient number, since it is larger than the sum of its proper divisors (1).

215768904809 is an equidigital number, since it uses as much as digits as its factorization.

215768904809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8709120, while the sum is 59.

The spelling of 215768904809 in words is "two hundred fifteen billion, seven hundred sixty-eight million, nine hundred four thousand, eight hundred nine".