218020931 has 2 divisors, whose sum is σ = 218020932. Its totient is φ = 218020930.

The previous prime is 218020889. The next prime is 218020939. The reversal of 218020931 is 139020812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 218020931 - 2²⁶ = 150912067 is a prime.

It is a super-2 number, since 2×218020931² = 95066252708213522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 218020931.

It is not a weakly prime, because it can be changed into another prime (218020939) 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, 109010465 + 109010466.

It is an arithmetic number, because the mean of its divisors is an integer number (109010466).

Almost surely, 2^218020931 is an apocalyptic number.

218020931 is a deficient number, since it is larger than the sum of its proper divisors (1).

218020931 is an equidigital number, since it uses as much as digits as its factorization.

218020931 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 218020931 is about 14765.5318563200. The cubic root of 218020931 is about 601.8654267023.

The spelling of 218020931 in words is "two hundred eighteen million, twenty thousand, nine hundred thirty-one".