216636257 has 4 divisors (see below), whose sum is σ = 217166340. Its totient is φ = 216106176.

The previous prime is 216636247. The next prime is 216636263. The reversal of 216636257 is 752636612.

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 136515856 + 80120401 = 11684^2 + 8951^2 .

It is a cyclic number.

It is not a de Polignac number, because 216636257 - 2¹² = 216632161 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 216636257.

It is not an unprimeable number, because it can be changed into a prime (216636247) 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, 264428 + ... + 265245.

It is an arithmetic number, because the mean of its divisors is an integer number (54291585).

Almost surely, 2^216636257 is an apocalyptic number.

It is an amenable number.

216636257 is a deficient number, since it is larger than the sum of its proper divisors (530083).

216636257 is an equidigital number, since it uses as much as digits as its factorization.

216636257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 530082.

The product of its digits is 90720, while the sum is 38.

The square root of 216636257 is about 14718.5684426170. The cubic root of 216636257 is about 600.5885493459.

The spelling of 216636257 in words is "two hundred sixteen million, six hundred thirty-six thousand, two hundred fifty-seven".