20808805 has 8 divisors (see below), whose sum is σ = 25831800. Its totient is φ = 16072896.

The previous prime is 20808803. The next prime is 20808829. The reversal of 20808805 is 50880802.

It can be written as a sum of positive squares in 4 ways, for example, as 7834401 + 12974404 = 2799^2 + 3602^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 20808805 - 2¹ = 20808803 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20808803) 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, 71610 + ... + 71899.

It is an arithmetic number, because the mean of its divisors is an integer number (3228975).

Almost surely, 2^20808805 is an apocalyptic number.

It is an amenable number.

20808805 is a deficient number, since it is larger than the sum of its proper divisors (5022995).

20808805 is a wasteful number, since it uses less digits than its factorization.

20808805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 143543.

The product of its (nonzero) digits is 5120, while the sum is 31.

The square root of 20808805 is about 4561.6669102424. Note that the first 3 decimals coincide. The cubic root of 20808805 is about 275.0525739704.

The spelling of 20808805 in words is "twenty million, eight hundred eight thousand, eight hundred five".