20405265 has 16 divisors (see below), whose sum is σ = 33265728. Its totient is φ = 10677056.

The previous prime is 20405251. The next prime is 20405269. The reversal of 20405265 is 56250402.

It is a cyclic number.

It is not a de Polignac number, because 20405265 - 2⁵ = 20405233 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20405269) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12039 + ... + 13628.

It is an arithmetic number, because the mean of its divisors is an integer number (2079108).

Almost surely, 2^20405265 is an apocalyptic number.

It is an amenable number.

20405265 is a deficient number, since it is larger than the sum of its proper divisors (12860463).

20405265 is a wasteful number, since it uses less digits than its factorization.

20405265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25728.

The product of its (nonzero) digits is 2400, while the sum is 24.

The square root of 20405265 is about 4517.2187239495. The cubic root of 20405265 is about 273.2629462159.

Adding to 20405265 its reverse (56250402), we get a palindrome (76655667).

The spelling of 20405265 in words is "twenty million, four hundred five thousand, two hundred sixty-five".