21424145 has 8 divisors (see below), whose sum is σ = 25736640. Its totient is φ = 17120880.

The previous prime is 21424129. The next prime is 21424159. The reversal of 21424145 is 54142412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21424145 - 2⁴ = 21424129 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21424145.

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, 4796 + ... + 8114.

It is an arithmetic number, because the mean of its divisors is an integer number (3217080).

Almost surely, 2^21424145 is an apocalyptic number.

It is an amenable number.

21424145 is a deficient number, since it is larger than the sum of its proper divisors (4312495).

21424145 is a wasteful number, since it uses less digits than its factorization.

21424145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4615.

The product of its digits is 1280, while the sum is 23.

The square root of 21424145 is about 4628.6223652400. The cubic root of 21424145 is about 277.7374857411.

Adding to 21424145 its reverse (54142412), we get a palindrome (75566557).

The spelling of 21424145 in words is "twenty-one million, four hundred twenty-four thousand, one hundred forty-five".