21125271 has 8 divisors (see below), whose sum is σ = 29823984. Its totient is φ = 13255040.

The previous prime is 21125267. The next prime is 21125303. The reversal of 21125271 is 17252112.

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

It is a cyclic number.

It is not a de Polignac number, because 21125271 - 2² = 21125267 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21125371) 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 7 ways as a sum of consecutive naturals, for example, 207060 + ... + 207161.

It is an arithmetic number, because the mean of its divisors is an integer number (3727998).

Almost surely, 2^21125271 is an apocalyptic number.

21125271 is a deficient number, since it is larger than the sum of its proper divisors (8698713).

21125271 is a wasteful number, since it uses less digits than its factorization.

21125271 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 414241.

The product of its digits is 280, while the sum is 21.

The square root of 21125271 is about 4596.2235585315. The cubic root of 21125271 is about 276.4399227680.

Adding to 21125271 its reverse (17252112), we get a palindrome (38377383).

The spelling of 21125271 in words is "twenty-one million, one hundred twenty-five thousand, two hundred seventy-one".