21111441 has 16 divisors (see below), whose sum is σ = 30401280. Its totient is φ = 12954240.

The previous prime is 21111397. The next prime is 21111457. The reversal of 21111441 is 14411112.

It is not a de Polignac number, because 21111441 - 2¹³ = 21103249 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21111441.

It is not an unprimeable number, because it can be changed into a prime (21111481) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19800 + ... + 20838.

It is an arithmetic number, because the mean of its divisors is an integer number (1900080).

Almost surely, 2^21111441 is an apocalyptic number.

It is an amenable number.

21111441 is a deficient number, since it is larger than the sum of its proper divisors (9289839).

21111441 is a wasteful number, since it uses less digits than its factorization.

21111441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1576.

The product of its digits is 32, while the sum is 15.

The square root of 21111441 is about 4594.7188162063. The cubic root of 21111441 is about 276.3795843115.

Adding to 21111441 its reverse (14411112), we get a palindrome (35522553).

The spelling of 21111441 in words is "twenty-one million, one hundred eleven thousand, four hundred forty-one".