2120221021 has 4 divisors (see below), whose sum is σ = 2139672700. Its totient is φ = 2100769344.

The previous prime is 2120221007. The next prime is 2120221043. The reversal of 2120221021 is 1201220212.

It is a happy number.

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 1673955396 + 446265625 = 40914^2 + 21125^2 .

It is a cyclic number.

It is not a de Polignac number, because 2120221021 - 2¹⁵ = 2120188253 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2120220992 and 2120221010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2120221321) 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, 9725676 + ... + 9725893.

It is an arithmetic number, because the mean of its divisors is an integer number (534918175).

Almost surely, 2^2120221021 is an apocalyptic number.

It is an amenable number.

2120221021 is a deficient number, since it is larger than the sum of its proper divisors (19451679).

2120221021 is a wasteful number, since it uses less digits than its factorization.

2120221021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19451678.

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 2120221021 is about 46045.8578050187. The cubic root of 2120221021 is about 1284.6762993331.

Adding to 2120221021 its reverse (1201220212), we get a palindrome (3321441233).

The spelling of 2120221021 in words is "two billion, one hundred twenty million, two hundred twenty-one thousand, twenty-one".