20206405 has 16 divisors (see below), whose sum is σ = 25663680. Its totient is φ = 15230592.

The previous prime is 20206391. The next prime is 20206427. The reversal of 20206405 is 50460202.

It is a cyclic number.

It is not a de Polignac number, because 20206405 - 2¹¹ = 20204357 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 21097 + ... + 22033.

It is an arithmetic number, because the mean of its divisors is an integer number (1603980).

Almost surely, 2^20206405 is an apocalyptic number.

It is an amenable number.

20206405 is a deficient number, since it is larger than the sum of its proper divisors (5457275).

20206405 is a wasteful number, since it uses less digits than its factorization.

20206405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1188.

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 20206405 is about 4495.1535012722. The cubic root of 20206405 is about 272.3723499427.

Adding to 20206405 its reverse (50460202), we get a palindrome (70666607).

The spelling of 20206405 in words is "twenty million, two hundred six thousand, four hundred five".