20911121 has 8 divisors (see below), whose sum is σ = 26071104. Its totient is φ = 16294320.

The previous prime is 20911087. The next prime is 20911123. The reversal of 20911121 is 12111902.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20911121 - 2¹⁸ = 20648977 is a prime.

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 20911121.

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 (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 135710 + ... + 135863.

It is an arithmetic number, because the mean of its divisors is an integer number (3258888).

Almost surely, 2^20911121 is an apocalyptic number.

It is an amenable number.

20911121 is a deficient number, since it is larger than the sum of its proper divisors (5159983).

20911121 is a wasteful number, since it uses less digits than its factorization.

20911121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 271591.

The product of its (nonzero) digits is 36, while the sum is 17.

The square root of 20911121 is about 4572.8679184949. The cubic root of 20911121 is about 275.5026443445.

The spelling of 20911121 in words is "twenty million, nine hundred eleven thousand, one hundred twenty-one".