211831812 has 18 divisors (see below), whose sum is σ = 535463838. Its totient is φ = 70610592.

The previous prime is 211831811. The next prime is 211831813. The reversal of 211831812 is 218138112.

It is an interprime number because it is at equal distance from previous prime (211831811) and next prime (211831813).

It can be written as a sum of positive squares in only one way, i.e., 182412036 + 29419776 = 13506^2 + 5424^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is not an unprimeable number, because it can be changed into a prime (211831811) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2942073 + ... + 2942144.

It is an arithmetic number, because the mean of its divisors is an integer number (29747991).

Almost surely, 2^211831812 is an apocalyptic number.

It is an amenable number.

211831812 is an abundant number, since it is smaller than the sum of its proper divisors (323632026).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

211831812 is a wasteful number, since it uses less digits than its factorization.

211831812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5884227 (or 5884222 counting only the distinct ones).

The product of its digits is 768, while the sum is 27.

The square root of 211831812 is about 14554.4430329711. The cubic root of 211831812 is about 596.1154716734.

Adding to 211831812 its reverse (218138112), we get a palindrome (429969924).

It can be divided in two parts, 2118 and 31812, that added together give a triangular number (33930 = T₂₆₀).

The spelling of 211831812 in words is "two hundred eleven million, eight hundred thirty-one thousand, eight hundred twelve".