21111002109 has 32 divisors (see below), whose sum is σ = 31979015040. Its totient is φ = 13760948736.

The previous prime is 21111002063. The next prime is 21111002117. The reversal of 21111002109 is 90120011112.

It is a happy number.

It is not a de Polignac number, because 21111002109 - 2⁷ = 21111001981 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21111002091 and 21111002100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111002149) 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 in 31 ways as a sum of consecutive naturals, for example, 168819 + ... + 265935.

It is an arithmetic number, because the mean of its divisors is an integer number (999344220).

Almost surely, 2^21111002109 is an apocalyptic number.

It is an amenable number.

21111002109 is a deficient number, since it is larger than the sum of its proper divisors (10868012931).

21111002109 is an equidigital number, since it uses as much as digits as its factorization.

21111002109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97306 (or 97300 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 18.

The spelling of 21111002109 in words is "twenty-one billion, one hundred eleven million, two thousand, one hundred nine".