21329999 has 2 divisors, whose sum is σ = 21330000. Its totient is φ = 21329998.

The previous prime is 21329983. The next prime is 21330047. The reversal of 21329999 is 99992312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21329999 - 2⁴ = 21329983 is a prime.

21329999 is a modest number, since divided by 9999 gives 2132 as remainder.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21329909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10664999 + 10665000.

It is an arithmetic number, because the mean of its divisors is an integer number (10665000).

Almost surely, 2^21329999 is an apocalyptic number.

21329999 is a deficient number, since it is larger than the sum of its proper divisors (1).

21329999 is an equidigital number, since it uses as much as digits as its factorization.

21329999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 78732, while the sum is 44.

The square root of 21329999 is about 4618.4411872406. The cubic root of 21329999 is about 277.3300596273.

The spelling of 21329999 in words is "twenty-one million, three hundred twenty-nine thousand, nine hundred ninety-nine".