163991720 has 32 divisors (see below), whose sum is σ = 369813600. Its totient is φ = 65448768.

The previous prime is 163991719. The next prime is 163991743. The reversal of 163991720 is 27199361.

It is a happy number.

163991720 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14291 + ... + 23069.

It is an arithmetic number, because the mean of its divisors is an integer number (11556675).

Almost surely, 2^163991720 is an apocalyptic number.

163991720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

163991720 is an abundant number, since it is smaller than the sum of its proper divisors (205821880).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

163991720 is a wasteful number, since it uses less digits than its factorization.

163991720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9257 (or 9253 counting only the distinct ones).

The product of its (nonzero) digits is 20412, while the sum is 38.

The square root of 163991720 is about 12805.9251910981. The cubic root of 163991720 is about 547.3611554820.

The spelling of 163991720 in words is "one hundred sixty-three million, nine hundred ninety-one thousand, seven hundred twenty".