20439289 has 4 divisors (see below), whose sum is σ = 22011556. Its totient is φ = 18867024.

The previous prime is 20439283. The next prime is 20439299. The reversal of 20439289 is 98293402.

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 8363664 + 12075625 = 2892^2 + 3475^2 .

It is a cyclic number.

It is not a de Polignac number, because 20439289 - 2⁵ = 20439257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20439283) 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, 786114 + ... + 786139.

It is an arithmetic number, because the mean of its divisors is an integer number (5502889).

Almost surely, 2^20439289 is an apocalyptic number.

It is an amenable number.

20439289 is a deficient number, since it is larger than the sum of its proper divisors (1572267).

20439289 is a wasteful number, since it uses less digits than its factorization.

20439289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1572266.

The product of its (nonzero) digits is 31104, while the sum is 37.

The square root of 20439289 is about 4520.9831895286. The cubic root of 20439289 is about 273.4147425893.

It can be divided in two parts, 204 and 39289, that added together give a palindrome (39493).

The spelling of 20439289 in words is "twenty million, four hundred thirty-nine thousand, two hundred eighty-nine".