821123540 has 24 divisors (see below), whose sum is σ = 1739624040. Its totient is φ = 325541888.

The previous prime is 821123539. The next prime is 821123543. The reversal of 821123540 is 45321128.

821123540 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 71824 + 821051716 = 268^2 + 28654^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821123543) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 179405 + ... + 183924.

It is an arithmetic number, because the mean of its divisors is an integer number (72484335).

Almost surely, 2^821123540 is an apocalyptic number.

It is an amenable number.

821123540 is an abundant number, since it is smaller than the sum of its proper divisors (918500500).

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

821123540 is a wasteful number, since it uses less digits than its factorization.

821123540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 363451 (or 363449 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 821123540 is about 28655.2532705611. The cubic root of 821123540 is about 936.4174559936.

Adding to 821123540 its reverse (45321128), we get a palindrome (866444668).

The spelling of 821123540 in words is "eight hundred twenty-one million, one hundred twenty-three thousand, five hundred forty".