20195911 has 4 divisors (see below), whose sum is σ = 20847424. Its totient is φ = 19544400.

The previous prime is 20195893. The next prime is 20195933. The reversal of 20195911 is 11959102.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 11959102 = 2 ⋅5979551.

It is a cyclic number.

It is not a de Polignac number, because 20195911 - 2⁷ = 20195783 is a prime.

It is a super-2 number, since 2×20195911² = 815749642239842, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20195911.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20195971) 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, 325710 + ... + 325771.

It is an arithmetic number, because the mean of its divisors is an integer number (5211856).

Almost surely, 2^20195911 is an apocalyptic number.

20195911 is a deficient number, since it is larger than the sum of its proper divisors (651513).

20195911 is an equidigital number, since it uses as much as digits as its factorization.

20195911 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 651512.

The product of its (nonzero) digits is 810, while the sum is 28.

The square root of 20195911 is about 4493.9860925463. The cubic root of 20195911 is about 272.3251904671.

The spelling of 20195911 in words is "twenty million, one hundred ninety-five thousand, nine hundred eleven".