21400441 has 6 divisors (see below), whose sum is σ = 22586442. Its totient is φ = 20273760.

The previous prime is 21400429. The next prime is 21400451. The reversal of 21400441 is 14400412.

It can be written as a sum of positive squares in only one way, i.e., 20793600 + 606841 = 4560^2 + 779^2 .

It is not a de Polignac number, because 21400441 - 2⁹ = 21399929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21400451) 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 5 ways as a sum of consecutive naturals, for example, 29280 + ... + 30001.

It is an arithmetic number, because the mean of its divisors is an integer number (3764407).

Almost surely, 2^21400441 is an apocalyptic number.

It is an amenable number.

21400441 is a deficient number, since it is larger than the sum of its proper divisors (1186001).

21400441 is an equidigital number, since it uses as much as digits as its factorization.

21400441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59319 (or 59300 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 21400441 is about 4626.0610674741. The cubic root of 21400441 is about 277.6350169474.

Adding to 21400441 its reverse (14400412), we get a palindrome (35800853).

The spelling of 21400441 in words is "twenty-one million, four hundred thousand, four hundred forty-one".