2101101021 has 6 divisors (see below), whose sum is σ = 3034923710. Its totient is φ = 1400734008.

The previous prime is 2101100999. The next prime is 2101101029. The reversal of 2101101021 is 1201011012.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 1827562500 + 273538521 = 42750^2 + 16539^2 .

It is not a de Polignac number, because 2101101021 - 2⁶ = 2101100957 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: 233455669 = 2101101021 / (2 + 1 + 0 + 1 + 1 + 0 + 1 + 0 + 2 + 1).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2101100994 and 2101101012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2101101029) 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, 116727826 + ... + 116727843.

Almost surely, 2^2101101021 is an apocalyptic number.

It is an amenable number.

2101101021 is a deficient number, since it is larger than the sum of its proper divisors (933822689).

2101101021 is a wasteful number, since it uses less digits than its factorization.

2101101021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 233455675 (or 233455672 counting only the distinct ones).

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

The square root of 2101101021 is about 45837.7684993500. The cubic root of 2101101021 is about 1280.8029266090.

Adding to 2101101021 its reverse (1201011012), we get a palindrome (3302112033).

Subtracting from 2101101021 its reverse (1201011012), we obtain a palindrome (900090009).

The spelling of 2101101021 in words is "two billion, one hundred one million, one hundred one thousand, twenty-one".