21271633 has 8 divisors (see below), whose sum is σ = 21941352. Its totient is φ = 20606976.

The previous prime is 21271567. The next prime is 21271637. The reversal of 21271633 is 33617212.

It can be written as a sum of positive squares in 4 ways, for example, as 17040384 + 4231249 = 4128^2 + 2057^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21271633 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21271598 and 21271607.

It is not an unprimeable number, because it can be changed into a prime (21271637) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8391 + ... + 10627.

It is an arithmetic number, because the mean of its divisors is an integer number (2742669).

Almost surely, 2^21271633 is an apocalyptic number.

It is an amenable number.

21271633 is a deficient number, since it is larger than the sum of its proper divisors (669719).

21271633 is a wasteful number, since it uses less digits than its factorization.

21271633 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2531.

The product of its digits is 1512, while the sum is 25.

The square root of 21271633 is about 4612.1180600674. The cubic root of 21271633 is about 277.0768726680.

Adding to 21271633 its reverse (33617212), we get a palindrome (54888845).

It can be divided in two parts, 21271 and 633, that added together give a square (21904 = 148²).

The spelling of 21271633 in words is "twenty-one million, two hundred seventy-one thousand, six hundred thirty-three".