811620810 has 540 divisors, whose sum is σ = 3021589494. Its totient is φ = 155675520.

The previous prime is 811620793. The next prime is 811620839. The reversal of 811620810 is 18026118.

It can be written as a sum of positive squares in 3 ways, for example, as 350101521 + 461519289 = 18711^2 + 21483^2 .

It is a super-2 number, since 2×811620810² = 1317456678450112200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 269 ways as a sum of consecutive naturals, for example, 62432364 + ... + 62432376.

Almost surely, 2^811620810 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 811620810, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1510794747).

811620810 is an abundant number, since it is smaller than the sum of its proper divisors (2209968684).

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

811620810 is a wasteful number, since it uses less digits than its factorization.

811620810 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81 (or 41 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 27.

The square root of 811620810 is about 28488.9594404569. The cubic root of 811620810 is about 932.7910947589.

Adding to 811620810 its reverse (18026118), we get a palindrome (829646928).

The spelling of 811620810 in words is "eight hundred eleven million, six hundred twenty thousand, eight hundred ten".