821465172 has 96 divisors (see below), whose sum is σ = 2356300800. Its totient is φ = 245397600.

The previous prime is 821465149. The next prime is 821465173. The reversal of 821465172 is 271564128.

821465172 is a `hidden beast` number, since 8 + 21 + 465 + 172 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821465173) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 79479 + ... + 89217.

It is an arithmetic number, because the mean of its divisors is an integer number (24544800).

Almost surely, 2^821465172 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 821465172, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1178150400).

821465172 is an abundant number, since it is smaller than the sum of its proper divisors (1534835628).

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

821465172 is a wasteful number, since it uses less digits than its factorization.

821465172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9834 (or 9826 counting only the distinct ones).

The product of its digits is 26880, while the sum is 36.

The square root of 821465172 is about 28661.2137216832. The cubic root of 821465172 is about 936.5473048313.

The spelling of 821465172 in words is "eight hundred twenty-one million, four hundred sixty-five thousand, one hundred seventy-two".