21724274 has 24 divisors (see below), whose sum is σ = 38500272. Its totient is φ = 9113520.

The previous prime is 21724271. The next prime is 21724303. The reversal of 21724274 is 47242712.

It is not an unprimeable number, because it can be changed into a prime (21724271) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 797 + ... + 6639.

It is an arithmetic number, because the mean of its divisors is an integer number (1604178).

Almost surely, 2^21724274 is an apocalyptic number.

21724274 is a deficient number, since it is larger than the sum of its proper divisors (16775998).

21724274 is a wasteful number, since it uses less digits than its factorization.

21724274 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5882 (or 5869 counting only the distinct ones).

The product of its digits is 6272, while the sum is 29.

The square root of 21724274 is about 4660.9305937763. The cubic root of 21724274 is about 279.0284097259.

Adding to 21724274 its reverse (47242712), we get a palindrome (68966986).

It can be divided in two parts, 2172 and 4274, that added together give a palindrome (6446).

The spelling of 21724274 in words is "twenty-one million, seven hundred twenty-four thousand, two hundred seventy-four".