21442245 has 16 divisors (see below), whose sum is σ = 37426752. Its totient is φ = 10396160.

The previous prime is 21442243. The next prime is 21442261. The reversal of 21442245 is 54224412.

It is a happy number.

It is not a de Polignac number, because 21442245 - 2¹ = 21442243 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21442243) 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, 64812 + ... + 65141.

It is an arithmetic number, because the mean of its divisors is an integer number (2339172).

Almost surely, 2^21442245 is an apocalyptic number.

It is an amenable number.

21442245 is a deficient number, since it is larger than the sum of its proper divisors (15984507).

21442245 is a wasteful number, since it uses less digits than its factorization.

21442245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129972.

The product of its digits is 2560, while the sum is 24.

The square root of 21442245 is about 4630.5771778473. The cubic root of 21442245 is about 277.8156784137.

Adding to 21442245 its reverse (54224412), we get a palindrome (75666657).

The spelling of 21442245 in words is "twenty-one million, four hundred forty-two thousand, two hundred forty-five".