21154441 has 16 divisors (see below), whose sum is σ = 26501760. Its totient is φ = 16404480.

The previous prime is 21154403. The next prime is 21154447. The reversal of 21154441 is 14445112.

It is a cyclic number.

It is not a de Polignac number, because 21154441 - 2⁹ = 21153929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21154447) 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, 19255 + ... + 20323.

It is an arithmetic number, because the mean of its divisors is an integer number (1656360).

Almost surely, 2^21154441 is an apocalyptic number.

It is an amenable number.

21154441 is a deficient number, since it is larger than the sum of its proper divisors (5347319).

21154441 is a wasteful number, since it uses less digits than its factorization.

21154441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1344.

The product of its digits is 640, while the sum is 22.

The square root of 21154441 is about 4599.3957211790. The cubic root of 21154441 is about 276.5671013162.

Adding to 21154441 its reverse (14445112), we get a palindrome (35599553).

It can be divided in two parts, 2115 and 4441, that added together give a palindrome (6556).

The spelling of 21154441 in words is "twenty-one million, one hundred fifty-four thousand, four hundred forty-one".