81202212 has 108 divisors (see below), whose sum is σ = 257212956. Its totient is φ = 21409920.

The previous prime is 81202171. The next prime is 81202243. The reversal of 81202212 is 21220218.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 22127616 + 59074596 = 4704^2 + 7686^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 21162 + ... + 24702.

Almost surely, 2^81202212 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 81202212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (128606478).

81202212 is an abundant number, since it is smaller than the sum of its proper divisors (176010744).

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

81202212 is a wasteful number, since it uses less digits than its factorization.

81202212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3578 (or 3566 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

The square root of 81202212 is about 9011.2269974738. The cubic root of 81202212 is about 433.0346214852.

The spelling of 81202212 in words is "eighty-one million, two hundred two thousand, two hundred twelve".