21229147 has 2 divisors, whose sum is σ = 21229148. Its totient is φ = 21229146.

The previous prime is 21229139. The next prime is 21229163. The reversal of 21229147 is 74192212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21229147 - 2³ = 21229139 is a prime.

It is not a weakly prime, because it can be changed into another prime (21229177) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10614573 + 10614574.

It is an arithmetic number, because the mean of its divisors is an integer number (10614574).

Almost surely, 2^21229147 is an apocalyptic number.

21229147 is a deficient number, since it is larger than the sum of its proper divisors (1).

21229147 is an equidigital number, since it uses as much as digits as its factorization.

21229147 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2016, while the sum is 28.

The square root of 21229147 is about 4607.5098480633. The cubic root of 21229147 is about 276.8922804448.

The spelling of 21229147 in words is "twenty-one million, two hundred twenty-nine thousand, one hundred forty-seven".