81212000 has 96 divisors (see below), whose sum is σ = 202849920. Its totient is φ = 31948800.

The previous prime is 81211987. The next prime is 81212039. The reversal of 81212000 is 21218.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 315872 + ... + 316128.

It is an arithmetic number, because the mean of its divisors is an integer number (2113020).

Almost surely, 2^81212000 is an apocalyptic number.

81212000 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81212000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101424960).

81212000 is an abundant number, since it is smaller than the sum of its proper divisors (121637920).

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

81212000 is a wasteful number, since it uses less digits than its factorization.

81212000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 361 (or 343 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

The square root of 81212000 is about 9011.7700813991. The cubic root of 81212000 is about 433.0520199135.

Adding to 81212000 its reverse (21218), we get a palindrome (81233218).

The spelling of 81212000 in words is "eighty-one million, two hundred twelve thousand".