821651200 has 216 divisors, whose sum is σ = 2224076400. Its totient is φ = 299335680.

The previous prime is 821651177. The next prime is 821651231. The reversal of 821651200 is 2156128.

It is a super-2 number, since 2×821651200² = 1350221388922880000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (25).

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 23 ways as a sum of consecutive naturals, for example, 3526284 + ... + 3526516.

It is an arithmetic number, because the mean of its divisors is an integer number (10296650).

Almost surely, 2^821651200 is an apocalyptic number.

821651200 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 821651200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1112038200).

821651200 is an abundant number, since it is smaller than the sum of its proper divisors (1402425200).

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

821651200 is a wasteful number, since it uses less digits than its factorization.

821651200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 307 (or 288 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 25.

The square root of 821651200 is about 28664.4588297076. The cubic root of 821651200 is about 936.6179959485.

The spelling of 821651200 in words is "eight hundred twenty-one million, six hundred fifty-one thousand, two hundred".