216217939 has 16 divisors (see below), whose sum is σ = 260856000. Its totient is φ = 178930752.

The previous prime is 216217927. The next prime is 216217999. The reversal of 216217939 is 939712612.

It is not a de Polignac number, because 216217939 - 2⁹ = 216217427 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216217919) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 922 + ... + 20815.

It is an arithmetic number, because the mean of its divisors is an integer number (16303500).

Almost surely, 2^216217939 is an apocalyptic number.

216217939 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

216217939 is a deficient number, since it is larger than the sum of its proper divisors (44638061).

216217939 is an equidigital number, since it uses as much as digits as its factorization.

216217939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21787 (or 21773 counting only the distinct ones).

The product of its digits is 40824, while the sum is 40.

The square root of 216217939 is about 14704.3510227415. The cubic root of 216217939 is about 600.2017275394.

It can be divided in two parts, 216217 and 939, that added together give a square (217156 = 466²).

The spelling of 216217939 in words is "two hundred sixteen million, two hundred seventeen thousand, nine hundred thirty-nine".