20911143 has 16 divisors (see below), whose sum is σ = 31398912. Its totient is φ = 12264000.

The previous prime is 20911129. The next prime is 20911157. The reversal of 20911143 is 34111902.

It is an interprime number because it is at equal distance from previous prime (20911129) and next prime (20911157).

It is not a de Polignac number, because 20911143 - 2⁴ = 20911127 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20911123) 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 15 ways as a sum of consecutive naturals, for example, 9198 + ... + 11243.

It is an arithmetic number, because the mean of its divisors is an integer number (1962432).

Almost surely, 2^20911143 is an apocalyptic number.

20911143 is a deficient number, since it is larger than the sum of its proper divisors (10487769).

20911143 is a wasteful number, since it uses less digits than its factorization.

20911143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20486.

The product of its (nonzero) digits is 216, while the sum is 21.

The square root of 20911143 is about 4572.8703239869. The cubic root of 20911143 is about 275.5027409606.

The spelling of 20911143 in words is "twenty million, nine hundred eleven thousand, one hundred forty-three".