21339801709 has 2 divisors, whose sum is σ = 21339801710. Its totient is φ = 21339801708.

The previous prime is 21339801671. The next prime is 21339801713. The reversal of 21339801709 is 90710893312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19176156484 + 2163645225 = 138478^2 + 46515^2 .

It is a cyclic number.

It is not a de Polignac number, because 21339801709 - 2¹⁷ = 21339670637 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21339801779) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10669900854 + 10669900855.

It is an arithmetic number, because the mean of its divisors is an integer number (10669900855).

Almost surely, 2^21339801709 is an apocalyptic number.

It is an amenable number.

21339801709 is a deficient number, since it is larger than the sum of its proper divisors (1).

21339801709 is an equidigital number, since it uses as much as digits as its factorization.

21339801709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 81648, while the sum is 43.

The spelling of 21339801709 in words is "twenty-one billion, three hundred thirty-nine million, eight hundred one thousand, seven hundred nine".