216399644 has 12 divisors (see below), whose sum is σ = 383493600. Its totient is φ = 106830048.

The previous prime is 216399641. The next prime is 216399661. The reversal of 216399644 is 446993612.

It is a happy number.

216399644 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 216399595 and 216399604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216399641) 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, 342089 + ... + 342720.

It is an arithmetic number, because the mean of its divisors is an integer number (31957800).

Almost surely, 2^216399644 is an apocalyptic number.

It is an amenable number.

216399644 is a deficient number, since it is larger than the sum of its proper divisors (167093956).

216399644 is a wasteful number, since it uses less digits than its factorization.

216399644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 684892 (or 684890 counting only the distinct ones).

The product of its digits is 279936, while the sum is 44.

The square root of 216399644 is about 14710.5283385744. The cubic root of 216399644 is about 600.3698127581.

The spelling of 216399644 in words is "two hundred sixteen million, three hundred ninety-nine thousand, six hundred forty-four".