16218931 has 2 divisors, whose sum is σ = 16218932. Its totient is φ = 16218930.

The previous prime is 16218929. The next prime is 16218941. The reversal of 16218931 is 13981261.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 16218931 - 2¹ = 16218929 is a prime.

It is a super-2 number, since 2×16218931² = 526107445565522, which contains 22 as substring.

Together with 16218929, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 16218893 and 16218902.

It is not a weakly prime, because it can be changed into another prime (16218911) 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 as a sum of consecutive naturals, namely, 8109465 + 8109466.

It is an arithmetic number, because the mean of its divisors is an integer number (8109466).

Almost surely, 2^16218931 is an apocalyptic number.

16218931 is a deficient number, since it is larger than the sum of its proper divisors (1).

16218931 is an equidigital number, since it uses as much as digits as its factorization.

16218931 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2592, while the sum is 31.

The square root of 16218931 is about 4027.2733952390. The cubic root of 16218931 is about 253.1283230982.

Subtracting from 16218931 its reverse (13981261), we obtain a triangular number (2237670 = T₂₁₁₅).

The spelling of 16218931 in words is "sixteen million, two hundred eighteen thousand, nine hundred thirty-one".