20808877 has 4 divisors (see below), whose sum is σ = 20918016. Its totient is φ = 20699740.

The previous prime is 20808871. The next prime is 20808881. The reversal of 20808877 is 77880802.

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, and also an emirpimes, since its reverse is a distinct semiprime: 77880802 = 2 ⋅38940401.

It is a cyclic number.

It is not a de Polignac number, because 20808877 - 2¹¹ = 20806829 is a prime.

It is a super-2 number, since 2×20808877² = 866018724002258, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20808871) by changing a digit.

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, 54283 + ... + 54664.

It is an arithmetic number, because the mean of its divisors is an integer number (5229504).

Almost surely, 2^20808877 is an apocalyptic number.

It is an amenable number.

20808877 is a deficient number, since it is larger than the sum of its proper divisors (109139).

20808877 is a wasteful number, since it uses less digits than its factorization.

20808877 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109138.

The product of its (nonzero) digits is 50176, while the sum is 40.

The square root of 20808877 is about 4561.6748020875. The cubic root of 20808877 is about 275.0528912041.

The spelling of 20808877 in words is "twenty million, eight hundred eight thousand, eight hundred seventy-seven".