821053440 has 288 divisors, whose sum is σ = 2913019200. Its totient is φ = 213811200.

The previous prime is 821053433. The next prime is 821053451. The reversal of 821053440 is 44350128.

821053440 is a `hidden beast` number, since 8 + 210 + 5 + 3 + 440 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5437365 + ... + 5437515.

It is an arithmetic number, because the mean of its divisors is an integer number (10114650).

Almost surely, 2^821053440 is an apocalyptic number.

821053440 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 821053440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1456509600).

821053440 is an abundant number, since it is smaller than the sum of its proper divisors (2091965760).

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

821053440 is a wasteful number, since it uses less digits than its factorization.

821053440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 243 (or 220 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 821053440 is about 28654.0300830442. The cubic root of 821053440 is about 936.3908076561.

The spelling of 821053440 in words is "eight hundred twenty-one million, fifty-three thousand, four hundred forty".