211989931 has 2 divisors, whose sum is σ = 211989932. Its totient is φ = 211989930.

The previous prime is 211989907. The next prime is 211989941. The reversal of 211989931 is 139989112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 211989931 - 2²³ = 203601323 is a prime.

It is a super-2 number, since 2×211989931² = 89879461690769522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (211989941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105994965 + 105994966.

It is an arithmetic number, because the mean of its divisors is an integer number (105994966).

Almost surely, 2^211989931 is an apocalyptic number.

211989931 is a deficient number, since it is larger than the sum of its proper divisors (1).

211989931 is an equidigital number, since it uses as much as digits as its factorization.

211989931 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 34992, while the sum is 43.

The square root of 211989931 is about 14559.8740035757. The cubic root of 211989931 is about 596.2637555702.

The spelling of 211989931 in words is "two hundred eleven million, nine hundred eighty-nine thousand, nine hundred thirty-one".