21099099617 has 2 divisors, whose sum is σ = 21099099618. Its totient is φ = 21099099616.

The previous prime is 21099099601. The next prime is 21099099643. The reversal of 21099099617 is 71699099012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20809793536 + 289306081 = 144256^2 + 17009^2 .

It is a cyclic number.

It is not a de Polignac number, because 21099099617 - 2⁴ = 21099099601 is a prime.

It is not a weakly prime, because it can be changed into another prime (21099095617) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10549549808 + 10549549809.

It is an arithmetic number, because the mean of its divisors is an integer number (10549549809).

Almost surely, 2^21099099617 is an apocalyptic number.

It is an amenable number.

21099099617 is a deficient number, since it is larger than the sum of its proper divisors (1).

21099099617 is an equidigital number, since it uses as much as digits as its factorization.

21099099617 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 551124, while the sum is 53.

The spelling of 21099099617 in words is "twenty-one billion, ninety-nine million, ninety-nine thousand, six hundred seventeen".