821572 has 12 divisors (see below), whose sum is σ = 1444716. Its totient is φ = 408800.

The previous prime is 821551. The next prime is 821573. The reversal of 821572 is 275128.

It can be written as a sum of positive squares in 2 ways, for example, as 746496 + 75076 = 864^2 + 274^2 .

It is an Ulam number.

It is a plaindrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (821573) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 822 + ... + 1522.

It is an arithmetic number, because the mean of its divisors is an integer number (120393).

2⁸²¹⁵⁷² is an apocalyptic number.

It is an amenable number.

821572 is a deficient number, since it is larger than the sum of its proper divisors (623144).

821572 is a wasteful number, since it uses less digits than its factorization.

821572 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 998 (or 996 counting only the distinct ones).

The product of its digits is 1120, while the sum is 25.

The square root of 821572 is about 906.4060900060. The cubic root of 821572 is about 93.6587901050.

The spelling of 821572 in words is "eight hundred twenty-one thousand, five hundred seventy-two".