163988981 has 12 divisors (see below), whose sum is σ = 186923520. Its totient is φ = 143404560.

The previous prime is 163988963. The next prime is 163989013. The reversal of 163988981 is 189889361.

It is not a de Polignac number, because 163988981 - 2⁶ = 163988917 is a prime.

It is a super-2 number, since 2×163988981² = 53784771778836722, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (163988281) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22325 + ... + 28746.

It is an arithmetic number, because the mean of its divisors is an integer number (15576960).

Almost surely, 2^163988981 is an apocalyptic number.

It is an amenable number.

163988981 is a deficient number, since it is larger than the sum of its proper divisors (22934539).

163988981 is a wasteful number, since it uses less digits than its factorization.

163988981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51116 (or 51103 counting only the distinct ones).

The product of its digits is 746496, while the sum is 53.

The square root of 163988981 is about 12805.8182479684. The cubic root of 163988981 is about 547.3581081116.

The spelling of 163988981 in words is "one hundred sixty-three million, nine hundred eighty-eight thousand, nine hundred eighty-one".