812121216 has 64 divisors (see below), whose sum is σ = 2178246720. Its totient is φ = 268065792.

The previous prime is 812121203. The next prime is 812121223. The reversal of 812121216 is 612121218.

It is a tau number, because it is divible by the number of its divisors (64).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is an alternating number because its digits alternate between even and odd.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29286 + ... + 49818.

It is an arithmetic number, because the mean of its divisors is an integer number (34035105).

Almost surely, 2^812121216 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 812121216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1089123360).

812121216 is an abundant number, since it is smaller than the sum of its proper divisors (1366125504).

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

812121216 is a wasteful number, since it uses less digits than its factorization.

812121216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20653 (or 20641 counting only the distinct ones).

The product of its digits is 384, while the sum is 24.

The square root of 812121216 is about 28497.7405420149. The cubic root of 812121216 is about 932.9827599461.

It can be divided in two parts, 81212 and 1216, that added together give a palindrome (82428).

The spelling of 812121216 in words is "eight hundred twelve million, one hundred twenty-one thousand, two hundred sixteen".