21110109989 has 2 divisors, whose sum is σ = 21110109990. Its totient is φ = 21110109988.

The previous prime is 21110109973. The next prime is 21110110027. The reversal of 21110109989 is 98990101112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12430020100 + 8680089889 = 111490^2 + 93167^2 .

It is a cyclic number.

It is not a de Polignac number, because 21110109989 - 2⁴ = 21110109973 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21110109089) 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, 10555054994 + 10555054995.

It is an arithmetic number, because the mean of its divisors is an integer number (10555054995).

Almost surely, 2^21110109989 is an apocalyptic number.

It is an amenable number.

21110109989 is a deficient number, since it is larger than the sum of its proper divisors (1).

21110109989 is an equidigital number, since it uses as much as digits as its factorization.

21110109989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11664, while the sum is 41.

The spelling of 21110109989 in words is "twenty-one billion, one hundred ten million, one hundred nine thousand, nine hundred eighty-nine".