820921212 has 72 divisors (see below), whose sum is σ = 2162487600. Its totient is φ = 262257408.

The previous prime is 820921207. The next prime is 820921219. The reversal of 820921212 is 212129028.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820921219) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 142288 + ... + 147944.

It is an arithmetic number, because the mean of its divisors is an integer number (30034550).

Almost surely, 2^820921212 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 820921212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1081243800).

820921212 is an abundant number, since it is smaller than the sum of its proper divisors (1341566388).

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

820921212 is a wasteful number, since it uses less digits than its factorization.

820921212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5835 (or 5830 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 27.

The square root of 820921212 is about 28651.7226707226. The cubic root of 820921212 is about 936.3405373874.

The spelling of 820921212 in words is "eight hundred twenty million, nine hundred twenty-one thousand, two hundred twelve".