216661201 has 4 divisors (see below), whose sum is σ = 223650304. Its totient is φ = 209672100.

The previous prime is 216661177. The next prime is 216661217. The reversal of 216661201 is 102166612.

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 216661201 - 2¹⁷ = 216530129 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216661231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3494505 + ... + 3494566.

It is an arithmetic number, because the mean of its divisors is an integer number (55912576).

Almost surely, 2^216661201 is an apocalyptic number.

It is an amenable number.

216661201 is a deficient number, since it is larger than the sum of its proper divisors (6989103).

216661201 is an equidigital number, since it uses as much as digits as its factorization.

216661201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6989102.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 216661201 is about 14719.4157832436. The cubic root of 216661201 is about 600.6115995130.

The spelling of 216661201 in words is "two hundred sixteen million, six hundred sixty-one thousand, two hundred one".