821661484 has 48 divisors (see below), whose sum is σ = 1694117376. Its totient is φ = 341366400.

The previous prime is 821661461. The next prime is 821661497. The reversal of 821661484 is 484166128.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 184929 + ... + 189319.

It is an arithmetic number, because the mean of its divisors is an integer number (35294112).

Almost surely, 2^821661484 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 821661484, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (847058688).

821661484 is an abundant number, since it is smaller than the sum of its proper divisors (872455892).

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

821661484 is a wasteful number, since it uses less digits than its factorization.

821661484 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4606 (or 4604 counting only the distinct ones).

The product of its digits is 73728, while the sum is 40.

The square root of 821661484 is about 28664.6382150551. The cubic root of 821661484 is about 936.6219035836.

The spelling of 821661484 in words is "eight hundred twenty-one million, six hundred sixty-one thousand, four hundred eighty-four".