21207272 has 16 divisors (see below), whose sum is σ = 39852000. Its totient is φ = 10580080.

The previous prime is 21207271. The next prime is 21207301. The reversal of 21207272 is 27270212.

21207272 is a modest number, since divided by 7272 gives 2120 as remainder.

It is not an unprimeable number, because it can be changed into a prime (21207271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1229 + ... + 6627.

It is an arithmetic number, because the mean of its divisors is an integer number (2490750).

Almost surely, 2^21207272 is an apocalyptic number.

It is an amenable number.

21207272 is a deficient number, since it is larger than the sum of its proper divisors (18644728).

21207272 is a wasteful number, since it uses less digits than its factorization.

21207272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5896 (or 5892 counting only the distinct ones).

The product of its (nonzero) digits is 784, while the sum is 23.

The square root of 21207272 is about 4605.1353943180. The cubic root of 21207272 is about 276.7971423742.

Adding to 21207272 its reverse (27270212), we get a palindrome (48477484).

The spelling of 21207272 in words is "twenty-one million, two hundred seven thousand, two hundred seventy-two".