20539439 has 4 divisors (see below), whose sum is σ = 20553624. Its totient is φ = 20525256.

The previous prime is 20539433. The next prime is 20539481. The reversal of 20539439 is 93493502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93493502 = 2 ⋅46746751.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20539439 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20539399 and 20539408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20539433) 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, 4637 + ... + 7910.

It is an arithmetic number, because the mean of its divisors is an integer number (5138406).

Almost surely, 2^20539439 is an apocalyptic number.

20539439 is a deficient number, since it is larger than the sum of its proper divisors (14185).

20539439 is a wasteful number, since it uses less digits than its factorization.

20539439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14184.

The product of its (nonzero) digits is 29160, while the sum is 35.

The square root of 20539439 is about 4532.0457852939. The cubic root of 20539439 is about 273.8605813888.

The spelling of 20539439 in words is "twenty million, five hundred thirty-nine thousand, four hundred thirty-nine".