821920344 has 128 divisors (see below), whose sum is σ = 2408179200. Its totient is φ = 228925440.

The previous prime is 821920339. The next prime is 821920357. The reversal of 821920344 is 443029128.

It is a congruent number.

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, 1424184 + ... + 1424760.

It is an arithmetic number, because the mean of its divisors is an integer number (18813900).

Almost surely, 2^821920344 is an apocalyptic number.

821920344 is a gapful number since it is divisible by the number (84) 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 821920344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1204089600).

821920344 is an abundant number, since it is smaller than the sum of its proper divisors (1586258856).

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

821920344 is a wasteful number, since it uses less digits than its factorization.

821920344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 793 (or 789 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 33.

The square root of 821920344 is about 28669.1531789832. The cubic root of 821920344 is about 936.7202524754.

The spelling of 821920344 in words is "eight hundred twenty-one million, nine hundred twenty thousand, three hundred forty-four".