21101100101 has 4 divisors (see below), whose sum is σ = 21298306752. Its totient is φ = 20903893452.

The previous prime is 21101100073. The next prime is 21101100109. The reversal of 21101100101 is 10100110112.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21101100101 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 (21101100109) 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, 98603165 + ... + 98603378.

It is an arithmetic number, because the mean of its divisors is an integer number (5324576688).

Almost surely, 2^21101100101 is an apocalyptic number.

It is an amenable number.

21101100101 is a deficient number, since it is larger than the sum of its proper divisors (197206651).

21101100101 is a wasteful number, since it uses less digits than its factorization.

21101100101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 197206650.

The product of its (nonzero) digits is 2, while the sum is 8.

Adding to 21101100101 its reverse (10100110112), we get a palindrome (31201210213).

The spelling of 21101100101 in words is "twenty-one billion, one hundred one million, one hundred thousand, one hundred one".