21403441 has 2 divisors, whose sum is σ = 21403442. Its totient is φ = 21403440.

The previous prime is 21403439. The next prime is 21403463. The reversal of 21403441 is 14430412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11189025 + 10214416 = 3345^2 + 3196^2 .

It is a cyclic number.

It is not a de Polignac number, because 21403441 - 2¹ = 21403439 is a prime.

Together with 21403439, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21403241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10701720 + 10701721.

It is an arithmetic number, because the mean of its divisors is an integer number (10701721).

Almost surely, 2^21403441 is an apocalyptic number.

It is an amenable number.

21403441 is a deficient number, since it is larger than the sum of its proper divisors (1).

21403441 is an equidigital number, since it uses as much as digits as its factorization.

21403441 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 384, while the sum is 19.

The square root of 21403441 is about 4626.3853060462. The cubic root of 21403441 is about 277.6479896728.

Adding to 21403441 its reverse (14430412), we get a palindrome (35833853).

The spelling of 21403441 in words is "twenty-one million, four hundred three thousand, four hundred forty-one".