821378400 has 72 divisors (see below), whose sum is σ = 2673594504. Its totient is φ = 219033600.

The previous prime is 821378399. The next prime is 821378401. The reversal of 821378400 is 4873128.

821378400 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (821378399) and next prime (821378401).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821378401) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 168721 + ... + 173520.

It is an arithmetic number, because the mean of its divisors is an integer number (37133257).

Almost surely, 2^821378400 is an apocalyptic number.

821378400 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

821378400 is an abundant number, since it is smaller than the sum of its proper divisors (1852216104).

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

821378400 is a wasteful number, since it uses less digits than its factorization.

821378400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 342264 (or 342251 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 33.

The square root of 821378400 is about 28659.6999286454. The cubic root of 821378400 is about 936.5143275987.

The spelling of 821378400 in words is "eight hundred twenty-one million, three hundred seventy-eight thousand, four hundred".