20505323 has 4 divisors (see below), whose sum is σ = 20708448. Its totient is φ = 20302200.

The previous prime is 20505307. The next prime is 20505341. The reversal of 20505323 is 32350502.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20505323 - 2⁴ = 20505307 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20505295 and 20505304.

It is not an unprimeable number, because it can be changed into a prime (20505623) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 101411 + ... + 101612.

It is an arithmetic number, because the mean of its divisors is an integer number (5177112).

Almost surely, 2^20505323 is an apocalyptic number.

20505323 is a deficient number, since it is larger than the sum of its proper divisors (203125).

20505323 is a wasteful number, since it uses less digits than its factorization.

20505323 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 203124.

The product of its (nonzero) digits is 900, while the sum is 20.

The square root of 20505323 is about 4528.2803579284. The cubic root of 20505323 is about 273.7088699214.

Adding to 20505323 its reverse (32350502), we get a palindrome (52855825).

The spelling of 20505323 in words is "twenty million, five hundred five thousand, three hundred twenty-three".