813551663 has 4 divisors (see below), whose sum is σ = 813766128. Its totient is φ = 813337200.

The previous prime is 813551659. The next prime is 813551719. The reversal of 813551663 is 366155318.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 813551663 - 2² = 813551659 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 (813550663) 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, 101438 + ... + 109163.

It is an arithmetic number, because the mean of its divisors is an integer number (203441532).

Almost surely, 2^813551663 is an apocalyptic number.

813551663 is a deficient number, since it is larger than the sum of its proper divisors (214465).

813551663 is a wasteful number, since it uses less digits than its factorization.

813551663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 214464.

The product of its digits is 64800, while the sum is 38.

The square root of 813551663 is about 28522.8270513286. The cubic root of 813551663 is about 933.5302149994.

The spelling of 813551663 in words is "eight hundred thirteen million, five hundred fifty-one thousand, six hundred sixty-three".