21171227 has 8 divisors (see below), whose sum is σ = 26395392. Its totient is φ = 16497000.

The previous prime is 21171217. The next prime is 21171251. The reversal of 21171227 is 72217112.

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 21171227 - 2²⁰ = 20122651 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21171217) 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, 137399 + ... + 137552.

It is an arithmetic number, because the mean of its divisors is an integer number (3299424).

Almost surely, 2^21171227 is an apocalyptic number.

21171227 is a deficient number, since it is larger than the sum of its proper divisors (5224165).

21171227 is a wasteful number, since it uses less digits than its factorization.

21171227 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 274969.

The product of its digits is 392, while the sum is 23.

The square root of 21171227 is about 4601.2201642608. The cubic root of 21171227 is about 276.6402337612.

Adding to 21171227 its reverse (72217112), we get a palindrome (93388339).

The spelling of 21171227 in words is "twenty-one million, one hundred seventy-one thousand, two hundred twenty-seven".