821194900 has 18 divisors (see below), whose sum is σ = 1781993150. Its totient is φ = 328477920.

The previous prime is 821194889. The next prime is 821194939. The reversal of 821194900 is 9491128.

It can be written as a sum of positive squares in 3 ways, for example, as 186759556 + 634435344 = 13666^2 + 25188^2 .

It is a super-2 number, since 2×821194900² = 1348722127572020000, which contains 22 as substring.

It is a congruent number.

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 5 ways as a sum of consecutive naturals, for example, 4105875 + ... + 4106074.

Almost surely, 2^821194900 is an apocalyptic number.

It is an amenable number.

821194900 is an abundant number, since it is smaller than the sum of its proper divisors (960798250).

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

821194900 is a wasteful number, since it uses less digits than its factorization.

821194900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8211963 (or 8211956 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 34.

The square root of 821194900 is about 28656.4983904175. The cubic root of 821194900 is about 936.4445817592. Note that the first 3 decimals are identical.

The spelling of 821194900 in words is "eight hundred twenty-one million, one hundred ninety-four thousand, nine hundred".