811890 has 64 divisors (see below), whose sum is σ = 2257920. Its totient is φ = 207360.

The previous prime is 811879. The next prime is 811897. The reversal of 811890 is 98118.

811890 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (811897) by changing a digit.

811890 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8322 + ... + 8418.

It is an arithmetic number, because the mean of its divisors is an integer number (35280).

2⁸¹¹⁸⁹⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 811890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1128960).

811890 is an abundant number, since it is smaller than the sum of its proper divisors (1446030).

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

811890 is a wasteful number, since it uses less digits than its factorization.

811890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144 (or 138 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 27.

The square root of 811890 is about 901.0493882135. The cubic root of 811890 is about 93.2894209529.

The spelling of 811890 in words is "eight hundred eleven thousand, eight hundred ninety".