21443329 has 2 divisors, whose sum is σ = 21443330. Its totient is φ = 21443328.

The previous prime is 21443321. The next prime is 21443333. The reversal of 21443329 is 92334412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13490929 + 7952400 = 3673^2 + 2820^2 .

It is a cyclic number.

It is not a de Polignac number, because 21443329 - 2³ = 21443321 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21443297 and 21443306.

It is not a weakly prime, because it can be changed into another prime (21443321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10721664 + 10721665.

It is an arithmetic number, because the mean of its divisors is an integer number (10721665).

Almost surely, 2^21443329 is an apocalyptic number.

It is an amenable number.

21443329 is a deficient number, since it is larger than the sum of its proper divisors (1).

21443329 is an equidigital number, since it uses as much as digits as its factorization.

21443329 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5184, while the sum is 28.

The square root of 21443329 is about 4630.6942244117. The cubic root of 21443329 is about 277.8203599372.

The spelling of 21443329 in words is "twenty-one million, four hundred forty-three thousand, three hundred twenty-nine".