21424372 has 6 divisors (see below), whose sum is σ = 37492658. Its totient is φ = 10712184.

The previous prime is 21424367. The next prime is 21424373. The reversal of 21424372 is 27342412.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 18198756 + 3225616 = 4266^2 + 1796^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21424373) 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 as a sum of consecutive naturals, namely, 2678043 + ... + 2678050.

Almost surely, 2^21424372 is an apocalyptic number.

It is an amenable number.

21424372 is a deficient number, since it is larger than the sum of its proper divisors (16068286).

21424372 is a wasteful number, since it uses less digits than its factorization.

21424372 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5356097 (or 5356095 counting only the distinct ones).

The product of its digits is 2688, while the sum is 25.

The square root of 21424372 is about 4628.6468865101. The cubic root of 21424372 is about 277.7384666621.

Adding to 21424372 its reverse (27342412), we get a palindrome (48766784).

The spelling of 21424372 in words is "twenty-one million, four hundred twenty-four thousand, three hundred seventy-two".