21002101101 has 6 divisors (see below), whose sum is σ = 30336368270. Its totient is φ = 14001400728.

The previous prime is 21002101097. The next prime is 21002101177. The reversal of 21002101101 is 10110120012.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 14677080201 + 6325020900 = 121149^2 + 79530^2 .

It is not a de Polignac number, because 21002101101 - 2² = 21002101097 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9), and also a Moran number because the ratio is a prime number: 2333566789 = 21002101101 / (2 + 1 + 0 + 0 + 2 + 1 + 0 + 1 + 1 + 0 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002101181) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1166783386 + ... + 1166783403.

Almost surely, 2^21002101101 is an apocalyptic number.

It is an amenable number.

21002101101 is a deficient number, since it is larger than the sum of its proper divisors (9334267169).

21002101101 is a wasteful number, since it uses less digits than its factorization.

21002101101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2333566795 (or 2333566792 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21002101101 its reverse (10110120012), we get a palindrome (31112221113).

The spelling of 21002101101 in words is "twenty-one billion, two million, one hundred one thousand, one hundred one".