821222438400 has 3240 divisors, whose sum is σ = 4011054151104. Its totient is φ = 158854348800.

The previous prime is 821222438287. The next prime is 821222438441. The reversal of 821222438400 is 4834222128.

821222438400 is a `hidden beast` number, since 8 + 2 + 1 + 2 + 2 + 243 + 8 + 400 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 323 ways as a sum of consecutive naturals, for example, 26491046385 + ... + 26491046415.

Almost surely, 2^821222438400 is an apocalyptic number.

821222438400 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 821222438400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2005527075552).

821222438400 is an abundant number, since it is smaller than the sum of its proper divisors (3189831712704).

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

821222438400 is a wasteful number, since it uses less digits than its factorization.

821222438400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130 (or 80 counting only the distinct ones).

The product of its (nonzero) digits is 49152, while the sum is 36.

The spelling of 821222438400 in words is "eight hundred twenty-one billion, two hundred twenty-two million, four hundred thirty-eight thousand, four hundred".