21729368 has 16 divisors (see below), whose sum is σ = 41118000. Its totient is φ = 10764576.

The previous prime is 21729361. The next prime is 21729377. The reversal of 21729368 is 86392712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21729361) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11588 + ... + 13331.

It is an arithmetic number, because the mean of its divisors is an integer number (2569875).

Almost surely, 2^21729368 is an apocalyptic number.

It is an amenable number.

21729368 is a deficient number, since it is larger than the sum of its proper divisors (19388632).

21729368 is a wasteful number, since it uses less digits than its factorization.

21729368 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25034 (or 25030 counting only the distinct ones).

The product of its digits is 36288, while the sum is 38.

The square root of 21729368 is about 4661.4770191432. The cubic root of 21729368 is about 279.0502172769.

The spelling of 21729368 in words is "twenty-one million, seven hundred twenty-nine thousand, three hundred sixty-eight".