21109938097 has 2 divisors, whose sum is σ = 21109938098. Its totient is φ = 21109938096.

The previous prime is 21109938067. The next prime is 21109938119. The reversal of 21109938097 is 79083990112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17280679936 + 3829258161 = 131456^2 + 61881^2 .

It is a cyclic number.

It is not a de Polignac number, because 21109938097 - 2²⁷ = 20975720369 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21109938097.

It is not a weakly prime, because it can be changed into another prime (21109938007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10554969048 + 10554969049.

It is an arithmetic number, because the mean of its divisors is an integer number (10554969049).

Almost surely, 2^21109938097 is an apocalyptic number.

It is an amenable number.

21109938097 is a deficient number, since it is larger than the sum of its proper divisors (1).

21109938097 is an equidigital number, since it uses as much as digits as its factorization.

21109938097 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 244944, while the sum is 49.

The spelling of 21109938097 in words is "twenty-one billion, one hundred nine million, nine hundred thirty-eight thousand, ninety-seven".