21423441 has 8 divisors (see below), whose sum is σ = 30761920. Its totient is φ = 13183632.

The previous prime is 21423421. The next prime is 21423487. The reversal of 21423441 is 14432412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21423441 - 2⁶ = 21423377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21423421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 274621 + ... + 274698.

It is an arithmetic number, because the mean of its divisors is an integer number (3845240).

Almost surely, 2^21423441 is an apocalyptic number.

It is an amenable number.

21423441 is a deficient number, since it is larger than the sum of its proper divisors (9338479).

21423441 is a wasteful number, since it uses less digits than its factorization.

21423441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 549335.

The product of its digits is 768, while the sum is 21.

The square root of 21423441 is about 4628.5463160694. The cubic root of 21423441 is about 277.7344435453.

Adding to 21423441 its reverse (14432412), we get a palindrome (35855853).

The spelling of 21423441 in words is "twenty-one million, four hundred twenty-three thousand, four hundred forty-one".