821645330 has 96 divisors (see below), whose sum is σ = 1744219008. Its totient is φ = 275686400.

The previous prime is 821645323. The next prime is 821645339. The reversal of 821645330 is 33546128.

It is not an unprimeable number, because it can be changed into a prime (821645339) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 9231926 + ... + 9232014.

It is an arithmetic number, because the mean of its divisors is an integer number (18168948).

Almost surely, 2^821645330 is an apocalyptic number.

821645330 is an abundant number, since it is smaller than the sum of its proper divisors (922573678).

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

821645330 is a wasteful number, since it uses less digits than its factorization.

821645330 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 260 (or 171 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 32.

The square root of 821645330 is about 28664.3564379178. The cubic root of 821645330 is about 936.6157654965.

The spelling of 821645330 in words is "eight hundred twenty-one million, six hundred forty-five thousand, three hundred thirty".