21442442 has 16 divisors (see below), whose sum is σ = 36822912. Its totient is φ = 9173520.

The previous prime is 21442439. The next prime is 21442451. The reversal of 21442442 is 24424412.

It is an unprimeable number.

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, 10592 + ... + 12452.

It is an arithmetic number, because the mean of its divisors is an integer number (2301432).

Almost surely, 2^21442442 is an apocalyptic number.

21442442 is a deficient number, since it is larger than the sum of its proper divisors (15380470).

21442442 is a wasteful number, since it uses less digits than its factorization.

21442442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2693.

The product of its digits is 2048, while the sum is 23.

The square root of 21442442 is about 4630.5984494447. The cubic root of 21442442 is about 277.8165292189.

Adding to 21442442 its reverse (24424412), we get a palindrome (45866854).

The spelling of 21442442 in words is "twenty-one million, four hundred forty-two thousand, four hundred forty-two".