821479440 has 160 divisors (see below), whose sum is σ = 2838568320. Its totient is φ = 195305472.

The previous prime is 821479427. The next prime is 821479453. The reversal of 821479440 is 44974128.

It is an interprime number because it is at equal distance from previous prime (821479427) and next prime (821479453).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 72222 + ... + 82818.

It is an arithmetic number, because the mean of its divisors is an integer number (17741052).

Almost surely, 2^821479440 is an apocalyptic number.

821479440 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 821479440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1419284160).

821479440 is an abundant number, since it is smaller than the sum of its proper divisors (2017088880).

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

821479440 is a wasteful number, since it uses less digits than its factorization.

821479440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10649 (or 10643 counting only the distinct ones).

The product of its (nonzero) digits is 64512, while the sum is 39.

The square root of 821479440 is about 28661.4626284145. The cubic root of 821479440 is about 936.5527270858.

The spelling of 821479440 in words is "eight hundred twenty-one million, four hundred seventy-nine thousand, four hundred forty".