20159989 has 4 divisors (see below), whose sum is σ = 20173356. Its totient is φ = 20146624.

The previous prime is 20159957. The next prime is 20160001. The reversal of 20159989 is 98995102.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11356900 + 8803089 = 3370^2 + 2967^2 .

It is a cyclic number.

It is not a de Polignac number, because 20159989 - 2⁵ = 20159957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20159929) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4084 + ... + 7549.

It is an arithmetic number, because the mean of its divisors is an integer number (5043339).

Almost surely, 2^20159989 is an apocalyptic number.

It is an amenable number.

20159989 is a deficient number, since it is larger than the sum of its proper divisors (13367).

20159989 is a wasteful number, since it uses less digits than its factorization.

20159989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13366.

The product of its (nonzero) digits is 58320, while the sum is 43.

The square root of 20159989 is about 4489.9876391812. The cubic root of 20159989 is about 272.1636351375.

The spelling of 20159989 in words is "twenty million, one hundred fifty-nine thousand, nine hundred eighty-nine".