811663 has 4 divisors (see below), whose sum is σ = 825480. Its totient is φ = 797848.

The previous prime is 811651. The next prime is 811667. The reversal of 811663 is 366118.

811663 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 366118 = 2 ⋅183059.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-811663 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (811667) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6820 + ... + 6937.

It is an arithmetic number, because the mean of its divisors is an integer number (206370).

2⁸¹¹⁶⁶³ is an apocalyptic number.

811663 is a deficient number, since it is larger than the sum of its proper divisors (13817).

811663 is a wasteful number, since it uses less digits than its factorization.

811663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13816.

The product of its digits is 864, while the sum is 25.

The square root of 811663 is about 900.9234151691. The cubic root of 811663 is about 93.2807257386.

The spelling of 811663 in words is "eight hundred eleven thousand, six hundred sixty-three".