820553663 has 8 divisors (see below), whose sum is σ = 847534080. Its totient is φ = 793605240.

The previous prime is 820553641. The next prime is 820553677. The reversal of 820553663 is 366355028.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 820553663 - 2¹² = 820549567 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 (820553633) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 51206 + ... + 65292.

It is an arithmetic number, because the mean of its divisors is an integer number (105941760).

Almost surely, 2^820553663 is an apocalyptic number.

820553663 is a deficient number, since it is larger than the sum of its proper divisors (26980417).

820553663 is a wasteful number, since it uses less digits than its factorization.

820553663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15997.

The product of its (nonzero) digits is 129600, while the sum is 38.

The square root of 820553663 is about 28645.3078705745. The cubic root of 820553663 is about 936.2007747249.

The spelling of 820553663 in words is "eight hundred twenty million, five hundred fifty-three thousand, six hundred sixty-three".