813237021 has 12 divisors (see below), whose sum is σ = 1175035680. Its totient is φ = 541991880.

The previous prime is 813237017. The next prime is 813237037. The reversal of 813237021 is 120732318.

It is not a de Polignac number, because 813237021 - 2² = 813237017 is a prime.

It is a super-2 number, since 2×813237021² = 1322708904649908882, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (813237001) 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 11 ways as a sum of consecutive naturals, for example, 22056 + ... + 45966.

It is an arithmetic number, because the mean of its divisors is an integer number (97919640).

Almost surely, 2^813237021 is an apocalyptic number.

It is an amenable number.

813237021 is a deficient number, since it is larger than the sum of its proper divisors (361798659).

813237021 is a wasteful number, since it uses less digits than its factorization.

813237021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27696 (or 27693 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 813237021 is about 28517.3109005741. The cubic root of 813237021 is about 933.4098515355.

Adding to 813237021 its reverse (120732318), we get a palindrome (933969339).

The spelling of 813237021 in words is "eight hundred thirteen million, two hundred thirty-seven thousand, twenty-one".