821211210 has 112 divisors (see below), whose sum is σ = 2236225536. Its totient is φ = 217020384.

The previous prime is 821211199. The next prime is 821211227. The reversal of 821211210 is 12112128.

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 (13) of ones.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 925387 + ... + 926273.

Almost surely, 2^821211210 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 821211210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1118112768).

821211210 is an abundant number, since it is smaller than the sum of its proper divisors (1415014326).

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

821211210 is a wasteful number, since it uses less digits than its factorization.

821211210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1039 (or 1024 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

The square root of 821211210 is about 28656.7829666905. The cubic root of 821211210 is about 936.4507813877.

Adding to 821211210 its reverse (12112128), we get a palindrome (833323338).

The spelling of 821211210 in words is "eight hundred twenty-one million, two hundred eleven thousand, two hundred ten".