21187227 has 8 divisors (see below), whose sum is σ = 28782864. Its totient is φ = 13858208.

The previous prime is 21187217. The next prime is 21187241. The reversal of 21187227 is 72278112.

It is a happy number.

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 21187227 - 2⁴ = 21187211 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21187194 and 21187203.

It is not an unprimeable number, because it can be changed into a prime (21187217) 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, 66468 + ... + 66785.

It is an arithmetic number, because the mean of its divisors is an integer number (3597858).

Almost surely, 2^21187227 is an apocalyptic number.

21187227 is a deficient number, since it is larger than the sum of its proper divisors (7595637).

21187227 is a wasteful number, since it uses less digits than its factorization.

21187227 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133309.

The product of its digits is 3136, while the sum is 30.

The square root of 21187227 is about 4602.9585051356. The cubic root of 21187227 is about 276.7099058240.

The spelling of 21187227 in words is "twenty-one million, one hundred eighty-seven thousand, two hundred twenty-seven".