163998643 has 4 divisors (see below), whose sum is σ = 173645640. Its totient is φ = 154351648.

The previous prime is 163998641. The next prime is 163998673. The reversal of 163998643 is 346899361.

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 163998643 - 2¹ = 163998641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (163998641) 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, 4823473 + ... + 4823506.

It is an arithmetic number, because the mean of its divisors is an integer number (43411410).

Almost surely, 2^163998643 is an apocalyptic number.

163998643 is a deficient number, since it is larger than the sum of its proper divisors (9646997).

163998643 is an equidigital number, since it uses as much as digits as its factorization.

163998643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9646996.

The product of its digits is 839808, while the sum is 49.

The square root of 163998643 is about 12806.1954928074. The cubic root of 163998643 is about 547.3688577570.

The spelling of 163998643 in words is "one hundred sixty-three million, nine hundred ninety-eight thousand, six hundred forty-three".