215065409 has 4 divisors (see below), whose sum is σ = 231608916. Its totient is φ = 198521904.

The previous prime is 215065397. The next prime is 215065429. The reversal of 215065409 is 904560512.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 102111025 + 112954384 = 10105^2 + 10628^2 .

It is a cyclic number.

It is not a de Polignac number, because 215065409 - 2²⁰ = 214016833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (215065429) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8271734 + ... + 8271759.

It is an arithmetic number, because the mean of its divisors is an integer number (57902229).

Almost surely, 2^215065409 is an apocalyptic number.

It is an amenable number.

215065409 is a deficient number, since it is larger than the sum of its proper divisors (16543507).

215065409 is a wasteful number, since it uses less digits than its factorization.

215065409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16543506.

The product of its (nonzero) digits is 10800, while the sum is 32.

The square root of 215065409 is about 14665.1085573889. The cubic root of 215065409 is about 599.1333868684.

The spelling of 215065409 in words is "two hundred fifteen million, sixty-five thousand, four hundred nine".