20123565 has 96 divisors (see below), whose sum is σ = 43338240. Its totient is φ = 7862400.

The previous prime is 20123549. The next prime is 20123573. The reversal of 20123565 is 56532102.

It is not a de Polignac number, because 20123565 - 2⁴ = 20123549 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 153550 + ... + 153680.

It is an arithmetic number, because the mean of its divisors is an integer number (451440).

Almost surely, 2^20123565 is an apocalyptic number.

It is an amenable number.

20123565 is an abundant number, since it is smaller than the sum of its proper divisors (23214675).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20123565 is a wasteful number, since it uses less digits than its factorization.

20123565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 183 (or 176 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 24.

The square root of 20123565 is about 4485.9296695334. The cubic root of 20123565 is about 271.9996260448. Note that the first 3 decimals are identical.

Adding to 20123565 its reverse (56532102), we get a palindrome (76655667).

The spelling of 20123565 in words is "twenty million, one hundred twenty-three thousand, five hundred sixty-five".