20163881 has 4 divisors (see below), whose sum is σ = 20419200. Its totient is φ = 19908564.

The previous prime is 20163863. The next prime is 20163889. The reversal of 20163881 is 18836102.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20163881 - 2⁶ = 20163817 is a prime.

It is a super-2 number, since 2×20163881² = 813164193964322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20163889) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 127541 + ... + 127698.

It is an arithmetic number, because the mean of its divisors is an integer number (5104800).

Almost surely, 2^20163881 is an apocalyptic number.

It is an amenable number.

20163881 is a deficient number, since it is larger than the sum of its proper divisors (255319).

20163881 is an equidigital number, since it uses as much as digits as its factorization.

20163881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 255318.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 20163881 is about 4490.4210270308. The cubic root of 20163881 is about 272.1811482540.

Adding to 20163881 its reverse (18836102), we get a palindrome (38999983).

The spelling of 20163881 in words is "twenty million, one hundred sixty-three thousand, eight hundred eighty-one".