21124365 has 16 divisors (see below), whose sum is σ = 33896448. Its totient is φ = 11233856.

The previous prime is 21124357. The next prime is 21124391. The reversal of 21124365 is 56342112.

It is a cyclic number.

It is not a de Polignac number, because 21124365 - 2³ = 21124357 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3907 + ... + 7583.

It is an arithmetic number, because the mean of its divisors is an integer number (2118528).

Almost surely, 2^21124365 is an apocalyptic number.

It is an amenable number.

21124365 is a deficient number, since it is larger than the sum of its proper divisors (12772083).

21124365 is a wasteful number, since it uses less digits than its factorization.

21124365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4068.

The product of its digits is 1440, while the sum is 24.

The square root of 21124365 is about 4596.1249983002. The cubic root of 21124365 is about 276.4359708163.

Adding to 21124365 its reverse (56342112), we get a palindrome (77466477).

The spelling of 21124365 in words is "twenty-one million, one hundred twenty-four thousand, three hundred sixty-five".