20023405 has 4 divisors (see below), whose sum is σ = 24028092. Its totient is φ = 16018720.

The previous prime is 20023403. The next prime is 20023411. The reversal of 20023405 is 50432002.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50432002 = 2 ⋅25216001.

It can be written as a sum of positive squares in 2 ways, for example, as 11485321 + 8538084 = 3389^2 + 2922^2 .

It is not a de Polignac number, because 20023405 - 2¹ = 20023403 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 (20023403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2002336 + ... + 2002345.

It is an arithmetic number, because the mean of its divisors is an integer number (6007023).

Almost surely, 2^20023405 is an apocalyptic number.

It is an amenable number.

20023405 is a deficient number, since it is larger than the sum of its proper divisors (4004687).

20023405 is an equidigital number, since it uses as much as digits as its factorization.

20023405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4004686.

The product of its (nonzero) digits is 240, while the sum is 16.

The square root of 20023405 is about 4474.7519484324. The cubic root of 20023405 is about 271.5476052896.

Adding to 20023405 its reverse (50432002), we get a palindrome (70455407).

The spelling of 20023405 in words is "twenty million, twenty-three thousand, four hundred five".