163506981 has 16 divisors (see below), whose sum is σ = 240187968. Its totient is φ = 98112000.

The previous prime is 163506979. The next prime is 163506991. The reversal of 163506981 is 189605361.

It is not a de Polignac number, because 163506981 - 2¹ = 163506979 is a prime.

It is a super-2 number, since 2×163506981² = 53469065671468722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (163506991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21196 + ... + 27861.

It is an arithmetic number, because the mean of its divisors is an integer number (15011748).

Almost surely, 2^163506981 is an apocalyptic number.

163506981 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

163506981 is a deficient number, since it is larger than the sum of its proper divisors (76680987).

163506981 is a wasteful number, since it uses less digits than its factorization.

163506981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49172.

The product of its (nonzero) digits is 38880, while the sum is 39.

The square root of 163506981 is about 12786.9848283323. The cubic root of 163506981 is about 546.8213128728.

The spelling of 163506981 in words is "one hundred sixty-three million, five hundred six thousand, nine hundred eighty-one".