21423241 has 12 divisors (see below), whose sum is σ = 26233680. Its totient is φ = 17395560.

The previous prime is 21423239. The next prime is 21423251. The reversal of 21423241 is 14232412.

It is not a de Polignac number, because 21423241 - 2¹ = 21423239 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is not an unprimeable number, because it can be changed into a prime (21423221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10575 + ... + 12436.

It is an arithmetic number, because the mean of its divisors is an integer number (2186140).

Almost surely, 2^21423241 is an apocalyptic number.

It is an amenable number.

21423241 is a deficient number, since it is larger than the sum of its proper divisors (4810439).

21423241 is a wasteful number, since it uses less digits than its factorization.

21423241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23044 (or 23037 counting only the distinct ones).

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

The square root of 21423241 is about 4628.5247109635. The cubic root of 21423241 is about 277.7335792729.

Adding to 21423241 its reverse (14232412), we get a palindrome (35655653).

It can be divided in two parts, 2 and 1423241, that multiplied together give a palindrome (2846482).

The spelling of 21423241 in words is "twenty-one million, four hundred twenty-three thousand, two hundred forty-one".