20505439 has 8 divisors (see below), whose sum is σ = 20880288. Its totient is φ = 20133120.

The previous prime is 20505431. The next prime is 20505449. The reversal of 20505439 is 93450502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20505439 - 2³ = 20505431 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 (20505431) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23499 + ... + 24355.

It is an arithmetic number, because the mean of its divisors is an integer number (2610036).

Almost surely, 2^20505439 is an apocalyptic number.

20505439 is a deficient number, since it is larger than the sum of its proper divisors (374849).

20505439 is an equidigital number, since it uses as much as digits as its factorization.

20505439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1265.

The product of its (nonzero) digits is 5400, while the sum is 28.

The square root of 20505439 is about 4528.2931663045. The cubic root of 20505439 is about 273.7093860503.

The spelling of 20505439 in words is "twenty million, five hundred five thousand, four hundred thirty-nine".