21442342 has 16 divisors (see below), whose sum is σ = 32643072. Its totient is φ = 10562760.

The previous prime is 21442331. The next prime is 21442349. The reversal of 21442342 is 24324412.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21442349) 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 7 ways as a sum of consecutive naturals, for example, 58243 + ... + 58609.

It is an arithmetic number, because the mean of its divisors is an integer number (2040192).

Almost surely, 2^21442342 is an apocalyptic number.

21442342 is a deficient number, since it is larger than the sum of its proper divisors (11200730).

21442342 is a wasteful number, since it uses less digits than its factorization.

21442342 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 723.

The product of its digits is 1536, while the sum is 22.

The square root of 21442342 is about 4630.5876516917. The cubic root of 21442342 is about 277.8160973387.

Adding to 21442342 its reverse (24324412), we get a palindrome (45766754).

The spelling of 21442342 in words is "twenty-one million, four hundred forty-two thousand, three hundred forty-two".