211993931 has 2 divisors, whose sum is σ = 211993932. Its totient is φ = 211993930.

The previous prime is 211993907. The next prime is 211993933. The reversal of 211993931 is 139399112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-211993931 is a prime.

It is a super-2 number, since 2×211993931² = 89882853561665522, which contains 22 as substring.

Together with 211993933, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (211993933) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105996965 + 105996966.

It is an arithmetic number, because the mean of its divisors is an integer number (105996966).

Almost surely, 2^211993931 is an apocalyptic number.

211993931 is a deficient number, since it is larger than the sum of its proper divisors (1).

211993931 is an equidigital number, since it uses as much as digits as its factorization.

211993931 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13122, while the sum is 38.

The square root of 211993931 is about 14560.0113667538. The cubic root of 211993931 is about 596.2675058112.

The spelling of 211993931 in words is "two hundred eleven million, nine hundred ninety-three thousand, nine hundred thirty-one".