21020000120221 has 4 divisors (see below), whose sum is σ = 21020016709692. Its totient is φ = 21019983530752.

The previous prime is 21020000120213. The next prime is 21020000120263. The reversal of 21020000120221 is 12202100002012.

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 7270513639321 + 13749486480900 = 2696389^2 + 3708030^2 .

It is a cyclic number.

It is not a de Polignac number, because 21020000120221 - 2³ = 21020000120213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020000120521) 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, 6221380 + ... + 8985853.

It is an arithmetic number, because the mean of its divisors is an integer number (5255004177423).

Almost surely, 2^{21020000120221} is an apocalyptic number.

It is an amenable number.

21020000120221 is a deficient number, since it is larger than the sum of its proper divisors (16589471).

21020000120221 is a wasteful number, since it uses less digits than its factorization.

21020000120221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16589470.

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

Adding to 21020000120221 its reverse (12202100002012), we get a palindrome (33222100122233).

The spelling of 21020000120221 in words is "twenty-one trillion, twenty billion, one hundred twenty thousand, two hundred twenty-one".