813222520 has 32 divisors (see below), whose sum is σ = 1996092720. Its totient is φ = 295717120.

The previous prime is 813222517. The next prime is 813222521. The reversal of 813222520 is 25222318.

It is a super-2 number, since 2×813222520² = 1322661734070300800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (813222521) 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, 923677 + ... + 924556.

Almost surely, 2^813222520 is an apocalyptic number.

It is an amenable number.

813222520 is an abundant number, since it is smaller than the sum of its proper divisors (1182870200).

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

813222520 is a wasteful number, since it uses less digits than its factorization.

813222520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1848255 (or 1848251 counting only the distinct ones).

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

The square root of 813222520 is about 28517.0566503628. The cubic root of 813222520 is about 933.4043035602.

Adding to 813222520 its reverse (25222318), we get a palindrome (838444838).

The spelling of 813222520 in words is "eight hundred thirteen million, two hundred twenty-two thousand, five hundred twenty".