21147211 has 2 divisors, whose sum is σ = 21147212. Its totient is φ = 21147210.

The previous prime is 21147197. The next prime is 21147223. The reversal of 21147211 is 11274112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21147211 - 2⁵ = 21147179 is a prime.

It is not a weakly prime, because it can be changed into another prime (21147241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10573605 + 10573606.

It is an arithmetic number, because the mean of its divisors is an integer number (10573606).

Almost surely, 2^21147211 is an apocalyptic number.

21147211 is a deficient number, since it is larger than the sum of its proper divisors (1).

21147211 is an equidigital number, since it uses as much as digits as its factorization.

21147211 is an evil number, because the sum of its binary digits is even.

The product of its digits is 112, while the sum is 19.

The square root of 21147211 is about 4598.6096811971. The cubic root of 21147211 is about 276.5355900764.

The spelling of 21147211 in words is "twenty-one million, one hundred forty-seven thousand, two hundred eleven".