21424365 has 16 divisors (see below), whose sum is σ = 38088000. Its totient is φ = 11426256.

The previous prime is 21424357. The next prime is 21424367. The reversal of 21424365 is 56342412.

It is not a de Polignac number, because 21424365 - 2³ = 21424357 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21424367) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 79215 + ... + 79484.

It is an arithmetic number, because the mean of its divisors is an integer number (2380500).

Almost surely, 2^21424365 is an apocalyptic number.

It is an amenable number.

21424365 is a deficient number, since it is larger than the sum of its proper divisors (16663635).

21424365 is a wasteful number, since it uses less digits than its factorization.

21424365 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158713 (or 158707 counting only the distinct ones).

The product of its digits is 5760, while the sum is 27.

The square root of 21424365 is about 4628.6461303496. The cubic root of 21424365 is about 277.7384364136.

Adding to 21424365 its reverse (56342412), we get a palindrome (77766777).

The spelling of 21424365 in words is "twenty-one million, four hundred twenty-four thousand, three hundred sixty-five".