821145600 has 546 divisors, whose sum is σ = 3330427836. Its totient is φ = 199065600.

The previous prime is 821145599. The next prime is 821145631. The reversal of 821145600 is 6541128.

821145600 is a `hidden beast` number, since 8 + 2 + 11 + 45 + 600 = 666.

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 41 ways as a sum of consecutive naturals, for example, 74649595 + ... + 74649605.

Almost surely, 2^821145600 is an apocalyptic number.

821145600 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 821145600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1665213918).

821145600 is an abundant number, since it is smaller than the sum of its proper divisors (2509282236).

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

821145600 is an equidigital number, since it uses as much as digits as its factorization.

821145600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63 (or 21 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 821145600 is about 28655.6381886707. The cubic root of 821145600 is about 936.4258417330.

Adding to 821145600 its reverse (6541128), we get a palindrome (827686728).

The spelling of 821145600 in words is "eight hundred twenty-one million, one hundred forty-five thousand, six hundred".