21430229 has 2 divisors, whose sum is σ = 21430230. Its totient is φ = 21430228.

The previous prime is 21430193. The next prime is 21430237. The reversal of 21430229 is 92203412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20160100 + 1270129 = 4490^2 + 1127^2 .

It is a cyclic number.

It is not a de Polignac number, because 21430229 - 2²⁰ = 20381653 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21430259) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10715114 + 10715115.

It is an arithmetic number, because the mean of its divisors is an integer number (10715115).

Almost surely, 2^21430229 is an apocalyptic number.

It is an amenable number.

21430229 is a deficient number, since it is larger than the sum of its proper divisors (1).

21430229 is an equidigital number, since it uses as much as digits as its factorization.

21430229 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 21430229 is about 4629.2795335776. The cubic root of 21430229 is about 277.7637737592.

The spelling of 21430229 in words is "twenty-one million, four hundred thirty thousand, two hundred twenty-nine".