821204530 has 8 divisors (see below), whose sum is σ = 1478168172. Its totient is φ = 328481808.

The previous prime is 821204473. The next prime is 821204537. The reversal of 821204530 is 35402128.

It can be written as a sum of positive squares in 2 ways, for example, as 754765729 + 66438801 = 27473^2 + 8151^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 821204495 and 821204504.

It is not an unprimeable number, because it can be changed into a prime (821204537) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41060217 + ... + 41060236.

Almost surely, 2^821204530 is an apocalyptic number.

821204530 is a deficient number, since it is larger than the sum of its proper divisors (656963642).

821204530 is a wasteful number, since it uses less digits than its factorization.

821204530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82120460.

The product of its (nonzero) digits is 1920, while the sum is 25.

The square root of 821204530 is about 28656.6664146408. Note that the first 3 decimals coincide. The cubic root of 821204530 is about 936.4482422487.

Adding to 821204530 its reverse (35402128), we get a palindrome (856606658).

The spelling of 821204530 in words is "eight hundred twenty-one million, two hundred four thousand, five hundred thirty".