21206272 has 18 divisors (see below), whose sum is σ = 42330218. Its totient is φ = 10603008.

The previous prime is 21206249. The next prime is 21206303. The reversal of 21206272 is 27260212.

It can be written as a sum of positive squares in only one way, i.e., 10863616 + 10342656 = 3296^2 + 3216^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41163 + ... + 41674.

Almost surely, 2^21206272 is an apocalyptic number.

It is an amenable number.

21206272 is a deficient number, since it is larger than the sum of its proper divisors (21123946).

21206272 is an frugal number, since it uses more digits than its factorization.

21206272 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82853 (or 82839 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 22.

The square root of 21206272 is about 4605.0268185973. The cubic root of 21206272 is about 276.7927916418.

Adding to 21206272 its reverse (27260212), we get a palindrome (48466484).

The spelling of 21206272 in words is "twenty-one million, two hundred six thousand, two hundred seventy-two".