21724076 has 12 divisors (see below), whose sum is σ = 41473320. Its totient is φ = 9874560.

The previous prime is 21724057. The next prime is 21724081. The reversal of 21724076 is 67042712.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 246821 + ... + 246908.

It is an arithmetic number, because the mean of its divisors is an integer number (3456110).

Almost surely, 2^21724076 is an apocalyptic number.

It is an amenable number.

21724076 is a deficient number, since it is larger than the sum of its proper divisors (19749244).

21724076 is a wasteful number, since it uses less digits than its factorization.

21724076 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 493744 (or 493742 counting only the distinct ones).

The product of its (nonzero) digits is 4704, while the sum is 29.

The square root of 21724076 is about 4660.9093533344. The cubic root of 21724076 is about 279.0275620138.

Adding to 21724076 its reverse (67042712), we get a palindrome (88766788).

The spelling of 21724076 in words is "twenty-one million, seven hundred twenty-four thousand, seventy-six".