21001100101 has 4 divisors (see below), whose sum is σ = 21004053100. Its totient is φ = 20998147104.

The previous prime is 21001100053. The next prime is 21001100117. The reversal of 21001100101 is 10100110012.

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 6086340225 + 14914759876 = 78015^2 + 122126^2 .

It is a cyclic number.

It is not a de Polignac number, because 21001100101 - 2²¹ = 20999002949 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 (21001101101) 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, 1465806 + ... + 1480063.

It is an arithmetic number, because the mean of its divisors is an integer number (5251013275).

Almost surely, 2^21001100101 is an apocalyptic number.

It is an amenable number.

21001100101 is a deficient number, since it is larger than the sum of its proper divisors (2952999).

21001100101 is an equidigital number, since it uses as much as digits as its factorization.

21001100101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2952998.

The product of its (nonzero) digits is 2, while the sum is 7.

Adding to 21001100101 its reverse (10100110012), we get a palindrome (31101210113).

The spelling of 21001100101 in words is "twenty-one billion, one million, one hundred thousand, one hundred one".