215288561 has 4 divisors (see below), whose sum is σ = 227952612. Its totient is φ = 202624512.

The previous prime is 215288539. The next prime is 215288569. The reversal of 215288561 is 165882512.

215288561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 189227536 + 26061025 = 13756^2 + 5105^2 .

It is a cyclic number.

It is not a de Polignac number, because 215288561 - 2⁶ = 215288497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (215288569) 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, 6332000 + ... + 6332033.

It is an arithmetic number, because the mean of its divisors is an integer number (56988153).

Almost surely, 2^215288561 is an apocalyptic number.

It is an amenable number.

215288561 is a deficient number, since it is larger than the sum of its proper divisors (12664051).

215288561 is a wasteful number, since it uses less digits than its factorization.

215288561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12664050.

The product of its digits is 38400, while the sum is 38.

The square root of 215288561 is about 14672.7148476347. The cubic root of 215288561 is about 599.3405356286.

The spelling of 215288561 in words is "two hundred fifteen million, two hundred eighty-eight thousand, five hundred sixty-one".