21011101009 has 2 divisors, whose sum is σ = 21011101010. Its totient is φ = 21011101008.

The previous prime is 21011100983. The next prime is 21011101103. The reversal of 21011101009 is 90010111012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18972307600 + 2038793409 = 137740^2 + 45153^2 .

It is a cyclic number.

It is not a de Polignac number, because 21011101009 - 2⁵ = 21011100977 is a prime.

It is a super-2 number, since 2×21011101009² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21011100983 and 21011101001.

It is not a weakly prime, because it can be changed into another prime (21011141009) 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, 10505550504 + 10505550505.

It is an arithmetic number, because the mean of its divisors is an integer number (10505550505).

Almost surely, 2^21011101009 is an apocalyptic number.

It is an amenable number.

21011101009 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011101009 is an equidigital number, since it uses as much as digits as its factorization.

21011101009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18, while the sum is 16.

The spelling of 21011101009 in words is "twenty-one billion, eleven million, one hundred one thousand, nine".