216677561 has 4 divisors (see below), whose sum is σ = 216991824. Its totient is φ = 216363300.

The previous prime is 216677521. The next prime is 216677599. The reversal of 216677561 is 165776612.

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 216677561 - 2¹⁴ = 216661177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216677521) 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, 156095 + ... + 157476.

It is an arithmetic number, because the mean of its divisors is an integer number (54247956).

Almost surely, 2^216677561 is an apocalyptic number.

It is an amenable number.

216677561 is a deficient number, since it is larger than the sum of its proper divisors (314263).

216677561 is an equidigital number, since it uses as much as digits as its factorization.

216677561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 314262.

The product of its digits is 105840, while the sum is 41.

The square root of 216677561 is about 14719.9715013311. The cubic root of 216677561 is about 600.6267164459.

The spelling of 216677561 in words is "two hundred sixteen million, six hundred seventy-seven thousand, five hundred sixty-one".