215017561 has 4 divisors (see below), whose sum is σ = 234564624. Its totient is φ = 195470500.

The previous prime is 215017529. The next prime is 215017567. The reversal of 215017561 is 165710512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 215017561 - 2⁵ = 215017529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (215017567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9773515 + ... + 9773536.

It is an arithmetic number, because the mean of its divisors is an integer number (58641156).

Almost surely, 2^215017561 is an apocalyptic number.

It is an amenable number.

215017561 is a deficient number, since it is larger than the sum of its proper divisors (19547063).

215017561 is a wasteful number, since it uses less digits than its factorization.

215017561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19547062.

The product of its (nonzero) digits is 2100, while the sum is 28.

The square root of 215017561 is about 14663.4771115176. The cubic root of 215017561 is about 599.0889516108.

The spelling of 215017561 in words is "two hundred fifteen million, seventeen thousand, five hundred sixty-one".