21234665 has 8 divisors (see below), whose sum is σ = 25557120. Its totient is φ = 16937392.

The previous prime is 21234623. The next prime is 21234667. The reversal of 21234665 is 56643212.

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

It is a cyclic number.

It is not a de Polignac number, because 21234665 - 2⁶ = 21234601 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21234667) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4385 + ... + 7854.

It is an arithmetic number, because the mean of its divisors is an integer number (3194640).

Almost surely, 2^21234665 is an apocalyptic number.

It is an amenable number.

21234665 is a deficient number, since it is larger than the sum of its proper divisors (4322455).

21234665 is a wasteful number, since it uses less digits than its factorization.

21234665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12591.

The product of its digits is 8640, while the sum is 29.

The square root of 21234665 is about 4608.1086141713. The cubic root of 21234665 is about 276.9162688359.

Adding to 21234665 its reverse (56643212), we get a palindrome (77877877).

The spelling of 21234665 in words is "twenty-one million, two hundred thirty-four thousand, six hundred sixty-five".