810530021 has 24 divisors (see below), whose sum is σ = 961868160. Its totient is φ = 680847552.

The previous prime is 810530011. The next prime is 810530057. The reversal of 810530021 is 120035018.

It is not a de Polignac number, because 810530021 - 2⁶ = 810529957 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 810529975 and 810530002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (810530011) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 784121 + ... + 785153.

It is an arithmetic number, because the mean of its divisors is an integer number (40077840).

Almost surely, 2^810530021 is an apocalyptic number.

It is an amenable number.

810530021 is a deficient number, since it is larger than the sum of its proper divisors (151338139).

810530021 is a wasteful number, since it uses less digits than its factorization.

810530021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1353 (or 1346 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 810530021 is about 28469.8089385932. The cubic root of 810530021 is about 932.3730282548.

Adding to 810530021 its reverse (120035018), we get a palindrome (930565039).

The spelling of 810530021 in words is "eight hundred ten million, five hundred thirty thousand, twenty-one".