21221020012321 has 4 divisors (see below), whose sum is σ = 21243571575444. Its totient is φ = 21198468449200.

The previous prime is 21221020012307. The next prime is 21221020012327. The reversal of 21221020012321 is 12321002012212.

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 5678383980096 + 15542636032225 = 2382936^2 + 3942415^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221020012321 - 2⁵ = 21221020012289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221020012327) 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, 11275780150 + ... + 11275782031.

It is an arithmetic number, because the mean of its divisors is an integer number (5310892893861).

Almost surely, 2^{21221020012321} is an apocalyptic number.

It is an amenable number.

21221020012321 is a deficient number, since it is larger than the sum of its proper divisors (22551563123).

21221020012321 is an equidigital number, since it uses as much as digits as its factorization.

21221020012321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22551563122.

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 21221020012321 its reverse (12321002012212), we get a palindrome (33542022024533).

The spelling of 21221020012321 in words is "twenty-one trillion, two hundred twenty-one billion, twenty million, twelve thousand, three hundred twenty-one".