21403443 has 16 divisors (see below), whose sum is σ = 30314880. Its totient is φ = 13394304.

The previous prime is 21403441. The next prime is 21403463. The reversal of 21403443 is 34430412.

It is not a de Polignac number, because 21403443 - 2¹ = 21403441 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21403441) 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 15 ways as a sum of consecutive naturals, for example, 4780 + ... + 8102.

It is an arithmetic number, because the mean of its divisors is an integer number (1894680).

Almost surely, 2^21403443 is an apocalyptic number.

21403443 is a deficient number, since it is larger than the sum of its proper divisors (8911437).

21403443 is a wasteful number, since it uses less digits than its factorization.

21403443 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3458.

The product of its (nonzero) digits is 1152, while the sum is 21.

The square root of 21403443 is about 4626.3855221976. The cubic root of 21403443 is about 277.6479983209.

Adding to 21403443 its reverse (34430412), we get a palindrome (55833855).

The spelling of 21403443 in words is "twenty-one million, four hundred three thousand, four hundred forty-three".