20216805 has 32 divisors (see below), whose sum is σ = 38166528. Its totient is φ = 8942400.

The previous prime is 20216761. The next prime is 20216827. The reversal of 20216805 is 50861202.

It is not a de Polignac number, because 20216805 - 2¹⁷ = 20085733 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 150 + ... + 6360.

It is an arithmetic number, because the mean of its divisors is an integer number (1192704).

Almost surely, 2^20216805 is an apocalyptic number.

It is an amenable number.

20216805 is a deficient number, since it is larger than the sum of its proper divisors (17949723).

20216805 is a wasteful number, since it uses less digits than its factorization.

20216805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6257.

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 20216805 is about 4496.3101538929. The cubic root of 20216805 is about 272.4190708809.

The spelling of 20216805 in words is "twenty million, two hundred sixteen thousand, eight hundred five".