821975040 has 240 divisors, whose sum is σ = 2949186240. Its totient is φ = 218972160.

The previous prime is 821975029. The next prime is 821975083. The reversal of 821975040 is 40579128.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 821974986 and 821975004.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 828945 + ... + 829935.

It is an arithmetic number, because the mean of its divisors is an integer number (12288276).

Almost surely, 2^821975040 is an apocalyptic number.

821975040 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 821975040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1474593120).

821975040 is an abundant number, since it is smaller than the sum of its proper divisors (2127211200).

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

821975040 is an equidigital number, since it uses as much as digits as its factorization.

821975040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1030 (or 1001 counting only the distinct ones).

The product of its (nonzero) digits is 20160, while the sum is 36.

The square root of 821975040 is about 28670.1070803721. The cubic root of 821975040 is about 936.7410305288.

The spelling of 821975040 in words is "eight hundred twenty-one million, nine hundred seventy-five thousand, forty".