20806431 has 4 divisors (see below), whose sum is σ = 27741912. Its totient is φ = 13870952.

The previous prime is 20806417. The next prime is 20806433. The reversal of 20806431 is 13460802.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20806431 - 2¹⁵ = 20773663 is a prime.

It is a super-2 number, since 2×20806431² = 865815141915522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20806433) 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 3 ways as a sum of consecutive naturals, for example, 3467736 + ... + 3467741.

It is an arithmetic number, because the mean of its divisors is an integer number (6935478).

Almost surely, 2^20806431 is an apocalyptic number.

20806431 is a deficient number, since it is larger than the sum of its proper divisors (6935481).

20806431 is an equidigital number, since it uses as much as digits as its factorization.

20806431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6935480.

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 20806431 is about 4561.4066909233. The cubic root of 20806431 is about 275.0421136606.

The spelling of 20806431 in words is "twenty million, eight hundred six thousand, four hundred thirty-one".