21424036 has 12 divisors (see below), whose sum is σ = 38505628. Its totient is φ = 10422432.

The previous prime is 21424027. The next prime is 21424049. The reversal of 21424036 is 63042412.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 16451136 + 4972900 = 4056^2 + 2230^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21423998 and 21424016.

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 3 ways as a sum of consecutive naturals, for example, 72231 + ... + 72526.

Almost surely, 2^21424036 is an apocalyptic number.

It is an amenable number.

21424036 is a deficient number, since it is larger than the sum of its proper divisors (17081592).

21424036 is a wasteful number, since it uses less digits than its factorization.

21424036 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144798 (or 144796 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 22.

The square root of 21424036 is about 4628.6105906632. The cubic root of 21424036 is about 277.7370147236.

Adding to 21424036 its reverse (63042412), we get a palindrome (84466448).

The spelling of 21424036 in words is "twenty-one million, four hundred twenty-four thousand, thirty-six".