216723819 has 16 divisors (see below), whose sum is σ = 311623200. Its totient is φ = 133184256.

The previous prime is 216723751. The next prime is 216723833. The reversal of 216723819 is 918327612.

It is a de Polignac number, because none of the positive numbers 2^k-216723819 is a prime.

It is a super-2 number, since 2×216723819² = 93938427443889522, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (216723839) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28117 + ... + 34985.

It is an arithmetic number, because the mean of its divisors is an integer number (19476450).

Almost surely, 2^216723819 is an apocalyptic number.

216723819 is a deficient number, since it is larger than the sum of its proper divisors (94899381).

216723819 is a wasteful number, since it uses less digits than its factorization.

216723819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7694.

The product of its digits is 36288, while the sum is 39.

The square root of 216723819 is about 14721.5426841075. The cubic root of 216723819 is about 600.6694555488.

The spelling of 216723819 in words is "two hundred sixteen million, seven hundred twenty-three thousand, eight hundred nineteen".