821975 has 36 divisors (see below), whose sum is σ = 1314648. Its totient is φ = 504000.

The previous prime is 821971. The next prime is 821993. The reversal of 821975 is 579128.

It is not a de Polignac number, because 821975 - 2² = 821971 is a prime.

It is a Duffinian number.

Its product of digits (5040) is a multiple of the sum of its prime divisors (84).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821971) 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 35 ways as a sum of consecutive naturals, for example, 13445 + ... + 13505.

It is an arithmetic number, because the mean of its divisors is an integer number (36518).

2⁸²¹⁹⁷⁵ is an apocalyptic number.

821975 is a deficient number, since it is larger than the sum of its proper divisors (492673).

821975 is a wasteful number, since it uses less digits than its factorization.

821975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96 (or 84 counting only the distinct ones).

The product of its digits is 5040, while the sum is 32.

The square root of 821975 is about 906.6283692892. The cubic root of 821975 is about 93.6741015334.

The spelling of 821975 in words is "eight hundred twenty-one thousand, nine hundred seventy-five".