21442213 has 12 divisors (see below), whose sum is σ = 23558688. Its totient is φ = 19503120.

The previous prime is 21442163. The next prime is 21442229. The reversal of 21442213 is 31224412.

It is a de Polignac number, because none of the positive numbers 2^k-21442213 is a prime.

It is a Duffinian number.

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 11 ways as a sum of consecutive naturals, for example, 11106 + ... + 12892.

It is an arithmetic number, because the mean of its divisors is an integer number (1963224).

Almost surely, 2^21442213 is an apocalyptic number.

It is an amenable number.

21442213 is a deficient number, since it is larger than the sum of its proper divisors (2116475).

21442213 is a wasteful number, since it uses less digits than its factorization.

21442213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1884 (or 1871 counting only the distinct ones).

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

The square root of 21442213 is about 4630.5737225532. The cubic root of 21442213 is about 277.8155402113.

Adding to 21442213 its reverse (31224412), we get a palindrome (52666625).

The spelling of 21442213 in words is "twenty-one million, four hundred forty-two thousand, two hundred thirteen".