821291328 has 336 divisors, whose sum is σ = 2829153600. Its totient is φ = 225838080.

The previous prime is 821291309. The next prime is 821291329. The reversal of 821291328 is 823192128.

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

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 821291292 and 821291301.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821291329) 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, 13920163 + ... + 13920221.

It is an arithmetic number, because the mean of its divisors is an integer number (8420100).

Almost surely, 2^821291328 is an apocalyptic number.

821291328 is a gapful number since it is divisible by the number (88) 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 821291328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1414576800).

821291328 is an abundant number, since it is smaller than the sum of its proper divisors (2007862272).

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

821291328 is a wasteful number, since it uses less digits than its factorization.

821291328 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127 (or 88 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

The square root of 821291328 is about 28658.1808215386. The cubic root of 821291328 is about 936.4812340179.

The spelling of 821291328 in words is "eight hundred twenty-one million, two hundred ninety-one thousand, three hundred twenty-eight".