21223042 has 4 divisors (see below), whose sum is σ = 31834566. Its totient is φ = 10611520.

The previous prime is 21223009. The next prime is 21223051. The reversal of 21223042 is 24032212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 15515721 + 5707321 = 3939^2 + 2389^2 .

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 5305759 + ... + 5305762.

Almost surely, 2^21223042 is an apocalyptic number.

21223042 is a deficient number, since it is larger than the sum of its proper divisors (10611524).

21223042 is a wasteful number, since it uses less digits than its factorization.

21223042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10611523.

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 21223042 is about 4606.8472950598. The cubic root of 21223042 is about 276.8657353455.

Adding to 21223042 its reverse (24032212), we get a palindrome (45255254).

The spelling of 21223042 in words is "twenty-one million, two hundred twenty-three thousand, forty-two".