20169989 has 4 divisors (see below), whose sum is σ = 23051424. Its totient is φ = 17288556.

The previous prime is 20169977. The next prime is 20169997. The reversal of 20169989 is 98996102.

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, and also an emirpimes, since its reverse is a distinct semiprime: 98996102 = 2 ⋅49498051.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20169989 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20169949) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 1440707 + ... + 1440720.

It is an arithmetic number, because the mean of its divisors is an integer number (5762856).

Almost surely, 2^20169989 is an apocalyptic number.

It is an amenable number.

20169989 is a deficient number, since it is larger than the sum of its proper divisors (2881435).

20169989 is an equidigital number, since it uses as much as digits as its factorization.

20169989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2881434.

The product of its (nonzero) digits is 69984, while the sum is 44.

The square root of 20169989 is about 4491.1010899333. The cubic root of 20169989 is about 272.2086283245.

The spelling of 20169989 in words is "twenty million, one hundred sixty-nine thousand, nine hundred eighty-nine".