81706212 has 192 divisors, whose sum is σ = 261488640. Its totient is φ = 21555072.

The previous prime is 81706201. The next prime is 81706217. The reversal of 81706212 is 21260718.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (81706217) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 643293 + ... + 643419.

It is an arithmetic number, because the mean of its divisors is an integer number (1361920).

Almost surely, 2^81706212 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81706212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (130744320).

81706212 is an abundant number, since it is smaller than the sum of its proper divisors (179782428).

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

81706212 is a wasteful number, since it uses less digits than its factorization.

81706212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 207 (or 199 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 81706212 is about 9039.1488537362. The cubic root of 81706212 is about 433.9286835891.

It can be divided in two parts, 81706 and 212, that added together give a palindrome (81918).

The spelling of 81706212 in words is "eighty-one million, seven hundred six thousand, two hundred twelve".