21111220202101 has 4 divisors (see below), whose sum is σ = 21111487062732. Its totient is φ = 21110953341472.

The previous prime is 21111220202081. The next prime is 21111220202201. The reversal of 21111220202101 is 10120202211112.

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 10123685787076 + 10987534415025 = 3181774^2 + 3314745^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21111220202101 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111220202201) 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, 133311616 + ... + 133469881.

It is an arithmetic number, because the mean of its divisors is an integer number (5277871765683).

Almost surely, 2^{21111220202101} is an apocalyptic number.

It is an amenable number.

21111220202101 is a deficient number, since it is larger than the sum of its proper divisors (266860631).

21111220202101 is an equidigital number, since it uses as much as digits as its factorization.

21111220202101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 266860630.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21111220202101 its reverse (10120202211112), we get a palindrome (31231422413213).

The spelling of 21111220202101 in words is "twenty-one trillion, one hundred eleven billion, two hundred twenty million, two hundred two thousand, one hundred one".