21829439 has 2 divisors, whose sum is σ = 21829440. Its totient is φ = 21829438.

The previous prime is 21829421. The next prime is 21829463. The reversal of 21829439 is 93492812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21829439 - 2²⁰ = 20780863 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 (21820439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10914719 + 10914720.

It is an arithmetic number, because the mean of its divisors is an integer number (10914720).

Almost surely, 2^21829439 is an apocalyptic number.

21829439 is a deficient number, since it is larger than the sum of its proper divisors (1).

21829439 is an equidigital number, since it uses as much as digits as its factorization.

21829439 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 31104, while the sum is 38.

The square root of 21829439 is about 4672.1985188988. The cubic root of 21829439 is about 279.4779345166.

The spelling of 21829439 in words is "twenty-one million, eight hundred twenty-nine thousand, four hundred thirty-nine".