21234717 has 40 divisors (see below), whose sum is σ = 38402496. Its totient is φ = 11415168.

The previous prime is 21234713. The next prime is 21234767. The reversal of 21234717 is 71743212.

It is a happy number.

It is not a de Polignac number, because 21234717 - 2² = 21234713 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 (21234713) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 8538 + ... + 10740.

Almost surely, 2^21234717 is an apocalyptic number.

21234717 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21234717 is a deficient number, since it is larger than the sum of its proper divisors (17167779).

21234717 is a wasteful number, since it uses less digits than its factorization.

21234717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2239 (or 2230 counting only the distinct ones).

The product of its digits is 2352, while the sum is 27.

The square root of 21234717 is about 4608.1142563960. The cubic root of 21234717 is about 276.9164948756.

Adding to 21234717 its reverse (71743212), we get a palindrome (92977929).

The spelling of 21234717 in words is "twenty-one million, two hundred thirty-four thousand, seven hundred seventeen".