813663 has 6 divisors (see below), whose sum is σ = 1175304. Its totient is φ = 542436.

The previous prime is 813647. The next prime is 813677. The reversal of 813663 is 366318.

It is not a de Polignac number, because 813663 - 2⁴ = 813647 is a prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 813663.

It is not an unprimeable number, because it can be changed into a prime (813613) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 45195 + ... + 45212.

It is an arithmetic number, because the mean of its divisors is an integer number (195884).

2⁸¹³⁶⁶³ is an apocalyptic number.

813663 is a deficient number, since it is larger than the sum of its proper divisors (361641).

813663 is a wasteful number, since it uses less digits than its factorization.

813663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90413 (or 90410 counting only the distinct ones).

The product of its digits is 2592, while the sum is 27.

The square root of 813663 is about 902.0327045069. The cubic root of 813663 is about 93.3572798533.

The spelling of 813663 in words is "eight hundred thirteen thousand, six hundred sixty-three".