21713244 has 24 divisors (see below), whose sum is σ = 57902208. Its totient is φ = 6203760.

The previous prime is 21713243. The next prime is 21713261. The reversal of 21713244 is 44231712.

It is a happy number.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21713243) 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, 129162 + ... + 129329.

It is an arithmetic number, because the mean of its divisors is an integer number (2412592).

Almost surely, 2^21713244 is an apocalyptic number.

It is an amenable number.

21713244 is an abundant number, since it is smaller than the sum of its proper divisors (36188964).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21713244 is a wasteful number, since it uses less digits than its factorization.

21713244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 258505 (or 258503 counting only the distinct ones).

The product of its digits is 1344, while the sum is 24.

The square root of 21713244 is about 4659.7472034436. The cubic root of 21713244 is about 278.9811783143.

Adding to 21713244 its reverse (44231712), we get a palindrome (65944956).

The spelling of 21713244 in words is "twenty-one million, seven hundred thirteen thousand, two hundred forty-four".