2011220021 has 4 divisors (see below), whose sum is σ = 2011393932. Its totient is φ = 2011046112.

The previous prime is 2011220011. The next prime is 2011220023. The reversal of 2011220021 is 1200221102.

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 1745986225 + 265233796 = 41785^2 + 16286^2 .

It is a cyclic number.

It is not a de Polignac number, because 2011220021 - 2⁶ = 2011219957 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 2011219984 and 2011220011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2011220023) 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, 68270 + ... + 93183.

It is an arithmetic number, because the mean of its divisors is an integer number (502848483).

Almost surely, 2^2011220021 is an apocalyptic number.

It is an amenable number.

2011220021 is a deficient number, since it is larger than the sum of its proper divisors (173911).

2011220021 is a wasteful number, since it uses less digits than its factorization.

2011220021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173910.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 2011220021 is about 44846.6277550498. The cubic root of 2011220021 is about 1262.2727145139.

Adding to 2011220021 its reverse (1200221102), we get a palindrome (3211441123).

The spelling of 2011220021 in words is "two billion, eleven million, two hundred twenty thousand, twenty-one".