20659439 has 4 divisors (see below), whose sum is σ = 20738256. Its totient is φ = 20580624.

The previous prime is 20659427. The next prime is 20659493. The reversal of 20659439 is 93495602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93495602 = 2 ⋅46747801.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20659439 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 (20659409) 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 3 ways as a sum of consecutive naturals, for example, 39014 + ... + 39539.

It is an arithmetic number, because the mean of its divisors is an integer number (5184564).

Almost surely, 2^20659439 is an apocalyptic number.

20659439 is a deficient number, since it is larger than the sum of its proper divisors (78817).

20659439 is an equidigital number, since it uses as much as digits as its factorization.

20659439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78816.

The product of its (nonzero) digits is 58320, while the sum is 38.

The square root of 20659439 is about 4545.2655587985. The cubic root of 20659439 is about 274.3928821391.

The spelling of 20659439 in words is "twenty million, six hundred fifty-nine thousand, four hundred thirty-nine".