81153212 has 36 divisors (see below), whose sum is σ = 169064280. Its totient is φ = 33967584.

The previous prime is 81153209. The next prime is 81153239. The reversal of 81153212 is 21235118.

It is a happy number.

81153212 is digitally balanced in base 9, because in such base it contains all the possibile digits an equal number of times.

81153212 is strictly pandigital in base 9.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3614 + ... + 13242.

It is an arithmetic number, because the mean of its divisors is an integer number (4696230).

Almost surely, 2^81153212 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 81153212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (84532140).

81153212 is an abundant number, since it is smaller than the sum of its proper divisors (87911068).

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

81153212 is a wasteful number, since it uses less digits than its factorization.

81153212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9690 (or 9681 counting only the distinct ones).

The product of its digits is 480, while the sum is 23.

The square root of 81153212 is about 9008.5077565599. The cubic root of 81153212 is about 432.9475016668.

The spelling of 81153212 in words is "eighty-one million, one hundred fifty-three thousand, two hundred twelve".