2121101021 has 4 divisors (see below), whose sum is σ = 2284262652. Its totient is φ = 1957939392.

The previous prime is 2121100997. The next prime is 2121101029. The reversal of 2121101021 is 1201011212.

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 1128220921 + 992880100 = 33589^2 + 31510^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121101021 - 2⁶ = 2121100957 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2121100993 and 2121101011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121101029) 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, 81580796 + ... + 81580821.

It is an arithmetic number, because the mean of its divisors is an integer number (571065663).

Almost surely, 2^2121101021 is an apocalyptic number.

It is an amenable number.

2121101021 is a deficient number, since it is larger than the sum of its proper divisors (163161631).

2121101021 is a wasteful number, since it uses less digits than its factorization.

2121101021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163161630.

The product of its (nonzero) digits is 8, while the sum is 11.

The square root of 2121101021 is about 46055.4125049380. The cubic root of 2121101021 is about 1284.8540101725.

Adding to 2121101021 its reverse (1201011212), we get a palindrome (3322112233).

The spelling of 2121101021 in words is "two billion, one hundred twenty-one million, one hundred one thousand, twenty-one".