21158382109 has 2 divisors, whose sum is σ = 21158382110. Its totient is φ = 21158382108.

The previous prime is 21158382101. The next prime is 21158382143. The reversal of 21158382109 is 90128385112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10820576484 + 10337805625 = 104022^2 + 101675^2 .

It is a cyclic number.

It is not a de Polignac number, because 21158382109 - 2³ = 21158382101 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21158382101) 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, 10579191054 + 10579191055.

It is an arithmetic number, because the mean of its divisors is an integer number (10579191055).

Almost surely, 2^21158382109 is an apocalyptic number.

It is an amenable number.

21158382109 is a deficient number, since it is larger than the sum of its proper divisors (1).

21158382109 is an equidigital number, since it uses as much as digits as its factorization.

21158382109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34560, while the sum is 40.

The spelling of 21158382109 in words is "twenty-one billion, one hundred fifty-eight million, three hundred eighty-two thousand, one hundred nine".