21300021929 has 2 divisors, whose sum is σ = 21300021930. Its totient is φ = 21300021928.

The previous prime is 21300021923. The next prime is 21300021931. The reversal of 21300021929 is 92912000312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20312805529 + 987216400 = 142523^2 + 31420^2 .

It is a cyclic number.

It is not a de Polignac number, because 21300021929 - 2¹² = 21300017833 is a prime.

Together with 21300021931, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21300021923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10650010964 + 10650010965.

It is an arithmetic number, because the mean of its divisors is an integer number (10650010965).

Almost surely, 2^21300021929 is an apocalyptic number.

It is an amenable number.

21300021929 is a deficient number, since it is larger than the sum of its proper divisors (1).

21300021929 is an equidigital number, since it uses as much as digits as its factorization.

21300021929 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1944, while the sum is 29.

The spelling of 21300021929 in words is "twenty-one billion, three hundred million, twenty-one thousand, nine hundred twenty-nine".