21187271 has 8 divisors (see below), whose sum is σ = 24729600. Its totient is φ = 17773848.

The previous prime is 21187259. The next prime is 21187279. The reversal of 21187271 is 17278112.

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 21187271 - 2¹⁴ = 21170887 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21187279) 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, 31871 + ... + 32528.

It is an arithmetic number, because the mean of its divisors is an integer number (3091200).

Almost surely, 2^21187271 is an apocalyptic number.

21187271 is a deficient number, since it is larger than the sum of its proper divisors (3542329).

21187271 is an equidigital number, since it uses as much as digits as its factorization.

21187271 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64453.

The product of its digits is 1568, while the sum is 29.

The square root of 21187271 is about 4602.9632846678. The cubic root of 21187271 is about 276.7100973738.

The spelling of 21187271 in words is "twenty-one million, one hundred eighty-seven thousand, two hundred seventy-one".