21115441 has 4 divisors (see below), whose sum is σ = 22226800. Its totient is φ = 20004084.

The previous prime is 21115439. The next prime is 21115453. The reversal of 21115441 is 14451112.

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.

It is a cyclic number.

It is not a de Polignac number, because 21115441 - 2¹ = 21115439 is a prime.

It is a super-3 number, since 3×21115441³ (a number of 23 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (19), and also a Moran number because the ratio is a prime number: 1111339 = 21115441 / (2 + 1 + 1 + 1 + 5 + 4 + 4 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21115421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 555651 + ... + 555688.

It is an arithmetic number, because the mean of its divisors is an integer number (5556700).

Almost surely, 2^21115441 is an apocalyptic number.

It is an amenable number.

21115441 is a deficient number, since it is larger than the sum of its proper divisors (1111359).

21115441 is a wasteful number, since it uses less digits than its factorization.

21115441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1111358.

The product of its digits is 160, while the sum is 19.

The square root of 21115441 is about 4595.1540779391. The cubic root of 21115441 is about 276.3970384892.

Adding to 21115441 its reverse (14451112), we get a palindrome (35566553).

The spelling of 21115441 in words is "twenty-one million, one hundred fifteen thousand, four hundred forty-one".