216144721 has 8 divisors (see below), whose sum is σ = 232976744. Its totient is φ = 199342080.

The previous prime is 216144707. The next prime is 216144727. The reversal of 216144721 is 127441612.

It can be written as a sum of positive squares in 4 ways, for example, as 3568321 + 212576400 = 1889^2 + 14580^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 216144721 - 2²³ = 207756113 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 216144721.

It is not an unprimeable number, because it can be changed into a prime (216144727) 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 7 ways as a sum of consecutive naturals, for example, 9361 + ... + 22801.

It is an arithmetic number, because the mean of its divisors is an integer number (29122093).

Almost surely, 2^216144721 is an apocalyptic number.

It is an amenable number.

216144721 is a deficient number, since it is larger than the sum of its proper divisors (16832023).

216144721 is a wasteful number, since it uses less digits than its factorization.

216144721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14691.

The product of its digits is 2688, while the sum is 28.

The square root of 216144721 is about 14701.8611406856. The cubic root of 216144721 is about 600.1339710100.

It can be divided in two parts, 21614 and 4721, that added together give a triangular number (26335 = T₂₂₉).

The spelling of 216144721 in words is "two hundred sixteen million, one hundred forty-four thousand, seven hundred twenty-one".