21345229 has 2 divisors, whose sum is σ = 21345230. Its totient is φ = 21345228.

The previous prime is 21345223. The next prime is 21345241. The reversal of 21345229 is 92254312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18688329 + 2656900 = 4323^2 + 1630^2 .

It is a cyclic number.

It is not a de Polignac number, because 21345229 - 2⁷ = 21345101 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21345197 and 21345206.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21345223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10672614 + 10672615.

It is an arithmetic number, because the mean of its divisors is an integer number (10672615).

Almost surely, 2^21345229 is an apocalyptic number.

It is an amenable number.

21345229 is a deficient number, since it is larger than the sum of its proper divisors (1).

21345229 is an equidigital number, since it uses as much as digits as its factorization.

21345229 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4320, while the sum is 28.

The square root of 21345229 is about 4620.0897177436. The cubic root of 21345229 is about 277.3960501279.

The spelling of 21345229 in words is "twenty-one million, three hundred forty-five thousand, two hundred twenty-nine".