821121125 has 36 divisors (see below), whose sum is σ = 1131243204. Its totient is φ = 594616000.

The previous prime is 821121101. The next prime is 821121127. The reversal of 821121125 is 521121128.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 6 ways, for example, as 522488164 + 298632961 = 22858^2 + 17281^2 .

It is not a de Polignac number, because 821121125 - 2⁸ = 821120869 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 821121125.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821121127) 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 35 ways as a sum of consecutive naturals, for example, 3524009 + ... + 3524241.

Almost surely, 2^821121125 is an apocalyptic number.

It is an amenable number.

821121125 is a deficient number, since it is larger than the sum of its proper divisors (310122079).

821121125 is an equidigital number, since it uses as much as digits as its factorization.

821121125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 503 (or 249 counting only the distinct ones).

The product of its digits is 320, while the sum is 23.

The square root of 821121125 is about 28655.2111316598. The cubic root of 821121125 is about 936.4165379627.

Multiplying 821121125 by its product of digits (320), we get a square (262758760000 = 512600²).

The spelling of 821121125 in words is "eight hundred twenty-one million, one hundred twenty-one thousand, one hundred twenty-five".