2101020121 has 4 divisors (see below), whose sum is σ = 2101998132. Its totient is φ = 2100042112.

The previous prime is 2101020049. The next prime is 2101020137. The reversal of 2101020121 is 1210201012.

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 148352400 + 1952667721 = 12180^2 + 44189^2 .

It is a cyclic number.

It is not a de Polignac number, because 2101020121 - 2⁷ = 2101019993 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2101020098 and 2101020107.

It is not an unprimeable number, because it can be changed into a prime (2101020151) 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, 485776 + ... + 490081.

It is an arithmetic number, because the mean of its divisors is an integer number (525499533).

Almost surely, 2^2101020121 is an apocalyptic number.

It is an amenable number.

2101020121 is a deficient number, since it is larger than the sum of its proper divisors (978011).

2101020121 is an equidigital number, since it uses as much as digits as its factorization.

2101020121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 978010.

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 2101020121 is about 45836.8860307940. The cubic root of 2101020121 is about 1280.7864878806.

Adding to 2101020121 its reverse (1210201012), we get a palindrome (3311221133).

The spelling of 2101020121 in words is "two billion, one hundred one million, twenty thousand, one hundred twenty-one".