21624242 has 16 divisors (see below), whose sum is σ = 34300800. Its totient is φ = 10195920.

The previous prime is 21624203. The next prime is 21624263. The reversal of 21624242 is 24242612.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7892 + ... + 10272.

It is an arithmetic number, because the mean of its divisors is an integer number (2143800).

Almost surely, 2^21624242 is an apocalyptic number.

21624242 is a deficient number, since it is larger than the sum of its proper divisors (12676558).

21624242 is a wasteful number, since it uses less digits than its factorization.

21624242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2641.

The product of its digits is 1536, while the sum is 23.

The square root of 21624242 is about 4650.1873080555. The cubic root of 21624242 is about 278.5994775426.

Adding to 21624242 its reverse (24242612), we get a palindrome (45866854).

The spelling of 21624242 in words is "twenty-one million, six hundred twenty-four thousand, two hundred forty-two".