821215616 has 48 divisors (see below), whose sum is σ = 1771590060. Its totient is φ = 379012608.

The previous prime is 821215613. The next prime is 821215657. The reversal of 821215616 is 616512128.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821215613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2651 + ... + 40613.

Almost surely, 2^821215616 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 821215616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (885795030).

821215616 is an abundant number, since it is smaller than the sum of its proper divisors (950374444).

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

821215616 is a wasteful number, since it uses less digits than its factorization.

821215616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38003 (or 37978 counting only the distinct ones).

The product of its digits is 5760, while the sum is 32.

The square root of 821215616 is about 28656.8598419296. The cubic root of 821215616 is about 936.4524561476.

The spelling of 821215616 in words is "eight hundred twenty-one million, two hundred fifteen thousand, six hundred sixteen".