20406806 has 16 divisors (see below), whose sum is σ = 35427840. Its totient is φ = 8634600.

The previous prime is 20406803. The next prime is 20406823. The reversal of 20406806 is 60860402.

It is a super-2 number, since 2×20406806² = 832875462243272, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20406803) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8120 + ... + 10331.

It is an arithmetic number, because the mean of its divisors is an integer number (2214240).

Almost surely, 2^20406806 is an apocalyptic number.

20406806 is a deficient number, since it is larger than the sum of its proper divisors (15021034).

20406806 is a wasteful number, since it uses less digits than its factorization.

20406806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18539.

The product of its (nonzero) digits is 2304, while the sum is 26.

The square root of 20406806 is about 4517.3892902870. The cubic root of 20406806 is about 273.2698249569.

It can be divided in two parts, 20406 and 806, that added together give a palindrome (21212).

The spelling of 20406806 in words is "twenty million, four hundred six thousand, eight hundred six".