821620800 has 1344 divisors, whose sum is σ = 4233062400. Its totient is φ = 149299200.

The previous prime is 821620763. The next prime is 821620831. The reversal of 821620800 is 8026128.

It is a tau number, because it is divible by the number of its divisors (1344).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 43243191 + ... + 43243209.

It is an arithmetic number, because the mean of its divisors is an integer number (3149600).

Almost surely, 2^821620800 is an apocalyptic number.

821620800 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 821620800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2116531200).

821620800 is an abundant number, since it is smaller than the sum of its proper divisors (3411441600).

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

821620800 is a wasteful number, since it uses less digits than its factorization.

821620800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81 (or 60 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 821620800 is about 28663.9285514041. The cubic root of 821620800 is about 936.6064445999.

Adding to 821620800 its reverse (8026128), we get a palindrome (829646928).

The spelling of 821620800 in words is "eight hundred twenty-one million, six hundred twenty thousand, eight hundred".