21111012101 has 4 divisors (see below), whose sum is σ = 21113525100. Its totient is φ = 21108499104.

The previous prime is 21111012071. The next prime is 21111012163. The reversal of 21111012101 is 10121011112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3223287076 + 17887725025 = 56774^2 + 133745^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21111012101 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111012191) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1243856 + ... + 1260713.

It is an arithmetic number, because the mean of its divisors is an integer number (5278381275).

Almost surely, 2^21111012101 is an apocalyptic number.

It is an amenable number.

21111012101 is a deficient number, since it is larger than the sum of its proper divisors (2512999).

21111012101 is an equidigital number, since it uses as much as digits as its factorization.

21111012101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2512998.

The product of its (nonzero) digits is 4, while the sum is 11.

Adding to 21111012101 its reverse (10121011112), we get a palindrome (31232023213).

The spelling of 21111012101 in words is "twenty-one billion, one hundred eleven million, twelve thousand, one hundred one".