21329927 has 2 divisors, whose sum is σ = 21329928. Its totient is φ = 21329926.

The previous prime is 21329923. The next prime is 21329929. The reversal of 21329927 is 72992312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21329927 - 2² = 21329923 is a prime.

Together with 21329929, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21329923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10664963 + 10664964.

It is an arithmetic number, because the mean of its divisors is an integer number (10664964).

Almost surely, 2^21329927 is an apocalyptic number.

21329927 is a deficient number, since it is larger than the sum of its proper divisors (1).

21329927 is an equidigital number, since it uses as much as digits as its factorization.

21329927 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13608, while the sum is 35.

The square root of 21329927 is about 4618.4333923962. The cubic root of 21329927 is about 277.3297475819.

The spelling of 21329927 in words is "twenty-one million, three hundred twenty-nine thousand, nine hundred twenty-seven".