20806390 has 16 divisors (see below), whose sum is σ = 40856400. Its totient is φ = 7565920.

The previous prime is 20806339. The next prime is 20806391. The reversal of 20806390 is 9360802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20806391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 94465 + ... + 94684.

It is an arithmetic number, because the mean of its divisors is an integer number (2553525).

Almost surely, 2^20806390 is an apocalyptic number.

20806390 is a deficient number, since it is larger than the sum of its proper divisors (20050010).

20806390 is a wasteful number, since it uses less digits than its factorization.

20806390 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189167.

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 20806390 is about 4561.4021966935. The cubic root of 20806390 is about 275.0419329995.

The spelling of 20806390 in words is "twenty million, eight hundred six thousand, three hundred ninety".