20439505 has 4 divisors (see below), whose sum is σ = 24527412. Its totient is φ = 16351600.

The previous prime is 20439493. The next prime is 20439541. The reversal of 20439505 is 50593402.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50593402 = 2 ⋅25296701.

It can be written as a sum of positive squares in 2 ways, for example, as 7392961 + 13046544 = 2719^2 + 3612^2 .

It is not a de Polignac number, because 20439505 - 2¹¹ = 20437457 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2043946 + ... + 2043955.

It is an arithmetic number, because the mean of its divisors is an integer number (6131853).

Almost surely, 2^20439505 is an apocalyptic number.

It is an amenable number.

20439505 is a deficient number, since it is larger than the sum of its proper divisors (4087907).

20439505 is an equidigital number, since it uses as much as digits as its factorization.

20439505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4087906.

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

The square root of 20439505 is about 4521.0070780745. The cubic root of 20439505 is about 273.4157057242.

The spelling of 20439505 in words is "twenty million, four hundred thirty-nine thousand, five hundred five".