20531806 has 8 divisors (see below), whose sum is σ = 30987144. Its totient is φ = 10202760.

The previous prime is 20531789. The next prime is 20531839. The reversal of 20531806 is 60813502.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31165 + ... + 31816.

It is an arithmetic number, because the mean of its divisors is an integer number (3873393).

Almost surely, 2^20531806 is an apocalyptic number.

20531806 is a deficient number, since it is larger than the sum of its proper divisors (10455338).

20531806 is a wasteful number, since it uses less digits than its factorization.

20531806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63146.

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 20531806 is about 4531.2035928658. The cubic root of 20531806 is about 273.8266525683.

The spelling of 20531806 in words is "twenty million, five hundred thirty-one thousand, eight hundred six".