20808069 has 4 divisors (see below), whose sum is σ = 27744096. Its totient is φ = 13872044.

The previous prime is 20808019. The next prime is 20808071. The reversal of 20808069 is 96080802.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20808069 is a prime.

It is a super-2 number, since 2×20808069² = 865951471017522, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20808019) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3468009 + ... + 3468014.

It is an arithmetic number, because the mean of its divisors is an integer number (6936024).

Almost surely, 2^20808069 is an apocalyptic number.

It is an amenable number.

20808069 is a deficient number, since it is larger than the sum of its proper divisors (6936027).

20808069 is an equidigital number, since it uses as much as digits as its factorization.

20808069 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6936026.

The product of its (nonzero) digits is 6912, while the sum is 33.

The square root of 20808069 is about 4561.5862372644. The cubic root of 20808069 is about 275.0493310951.

The spelling of 20808069 in words is "twenty million, eight hundred eight thousand, sixty-nine".