20820806 has 4 divisors (see below), whose sum is σ = 31231212. Its totient is φ = 10410402.

The previous prime is 20820797. The next prime is 20820817. The reversal of 20820806 is 60802802.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5205200 + ... + 5205203.

It is an arithmetic number, because the mean of its divisors is an integer number (7807803).

Almost surely, 2^20820806 is an apocalyptic number.

20820806 is a deficient number, since it is larger than the sum of its proper divisors (10410406).

20820806 is a wasteful number, since it uses less digits than its factorization.

20820806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10410405.

The product of its (nonzero) digits is 1536, while the sum is 26.

The square root of 20820806 is about 4562.9821389087. The cubic root of 20820806 is about 275.1054405585.

The spelling of 20820806 in words is "twenty million, eight hundred twenty thousand, eight hundred six".