216561648 has 40 divisors (see below), whose sum is σ = 560678400. Its totient is φ = 72028864.

The previous prime is 216561643. The next prime is 216561661. The reversal of 216561648 is 846165612.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216561641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18283 + ... + 27701.

It is an arithmetic number, because the mean of its divisors is an integer number (14016960).

Almost surely, 2^216561648 is an apocalyptic number.

It is an amenable number.

216561648 is an abundant number, since it is smaller than the sum of its proper divisors (344116752).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

216561648 is a wasteful number, since it uses less digits than its factorization.

216561648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9909 (or 9903 counting only the distinct ones).

The product of its digits is 69120, while the sum is 39.

The square root of 216561648 is about 14716.0337047725. The cubic root of 216561648 is about 600.5195943507.

The spelling of 216561648 in words is "two hundred sixteen million, five hundred sixty-one thousand, six hundred forty-eight".