216648961 has 9 divisors (see below), whose sum is σ = 222682243. Its totient is φ = 210776080.

The previous prime is 216648953. The next prime is 216649019. The reversal of 216648961 is 169846612.

The square root of 216648961 is 14719.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 10439361 + 206209600 = 3231^2 + 14360^2 .

It is not a de Polignac number, because 216648961 - 2³ = 216648953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216648941) 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 8 ways as a sum of consecutive naturals, for example, 603300 + ... + 603658.

Almost surely, 2^216648961 is an apocalyptic number.

216648961 is the 14719-th square number.

216648961 is the 7360-th centered octagonal number.

It is an amenable number.

216648961 is a deficient number, since it is larger than the sum of its proper divisors (6033282).

216648961 is an frugal number, since it uses more digits than its factorization.

216648961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 800 (or 400 counting only the distinct ones).

The product of its digits is 124416, while the sum is 43.

The cubic root of 216648961 is about 600.6002890363.

It can be divided in two parts, 21664 and 8961, that added together give a square (30625 = 175²).

The spelling of 216648961 in words is "two hundred sixteen million, six hundred forty-eight thousand, nine hundred sixty-one".