216731329 has 4 divisors (see below), whose sum is σ = 217866240. Its totient is φ = 215596420.

The previous prime is 216731327. The next prime is 216731381. The reversal of 216731329 is 923137612.

216731329 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 216731329 - 2¹ = 216731327 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 216731294 and 216731303.

It is not an unprimeable number, because it can be changed into a prime (216731321) 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, 567169 + ... + 567550.

It is an arithmetic number, because the mean of its divisors is an integer number (54466560).

Almost surely, 2^216731329 is an apocalyptic number.

It is an amenable number.

216731329 is a deficient number, since it is larger than the sum of its proper divisors (1134911).

216731329 is a wasteful number, since it uses less digits than its factorization.

216731329 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1134910.

The product of its digits is 13608, while the sum is 34.

The square root of 216731329 is about 14721.7977502749. The cubic root of 216731329 is about 600.6763936809.

The spelling of 216731329 in words is "two hundred sixteen million, seven hundred thirty-one thousand, three hundred twenty-nine".