21372424 has 16 divisors (see below), whose sum is σ = 40194000. Its totient is φ = 10654032.

The previous prime is 21372413. The next prime is 21372427. The reversal of 21372424 is 42427312.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21372427) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1074 + ... + 6625.

It is an arithmetic number, because the mean of its divisors is an integer number (2512125).

Almost surely, 2^21372424 is an apocalyptic number.

It is an amenable number.

21372424 is a deficient number, since it is larger than the sum of its proper divisors (18821576).

21372424 is a wasteful number, since it uses less digits than its factorization.

21372424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8052 (or 8048 counting only the distinct ones).

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

The square root of 21372424 is about 4623.0319055788. The cubic root of 21372424 is about 277.5138060929.

Adding to 21372424 its reverse (42427312), we get a palindrome (63799736).

The spelling of 21372424 in words is "twenty-one million, three hundred seventy-two thousand, four hundred twenty-four".