21101106989 has 2 divisors, whose sum is σ = 21101106990. Its totient is φ = 21101106988.

The previous prime is 21101106977. The next prime is 21101107009. The reversal of 21101106989 is 98960110112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12202958089 + 8898148900 = 110467^2 + 94330^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21101106989 is a prime.

It is a super-2 number, since 2×21101106989² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21101100989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550553494 + 10550553495.

It is an arithmetic number, because the mean of its divisors is an integer number (10550553495).

Almost surely, 2^21101106989 is an apocalyptic number.

It is an amenable number.

21101106989 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101106989 is an equidigital number, since it uses as much as digits as its factorization.

21101106989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7776, while the sum is 38.

The spelling of 21101106989 in words is "twenty-one billion, one hundred one million, one hundred six thousand, nine hundred eighty-nine".