20136405 has 32 divisors (see below), whose sum is σ = 33390720. Its totient is φ = 10356480.

The previous prime is 20136383. The next prime is 20136407. The reversal of 20136405 is 50463102.

It is a happy number.

It is not a de Polignac number, because 20136405 - 2⁹ = 20135893 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20136407) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 53799 + ... + 54171.

It is an arithmetic number, because the mean of its divisors is an integer number (1043460).

Almost surely, 2^20136405 is an apocalyptic number.

It is an amenable number.

20136405 is a deficient number, since it is larger than the sum of its proper divisors (13254315).

20136405 is a wasteful number, since it uses less digits than its factorization.

20136405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 501.

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 20136405 is about 4487.3605827925. The cubic root of 20136405 is about 272.0574642502.

Adding to 20136405 its reverse (50463102), we get a palindrome (70599507).

The spelling of 20136405 in words is "twenty million, one hundred thirty-six thousand, four hundred five".