20421305214221 has 8 divisors (see below), whose sum is σ = 20929156767288. Its totient is φ = 19913918944000.

The previous prime is 20421305214217. The next prime is 20421305214227. The reversal of 20421305214221 is 12241250312402.

It can be written as a sum of positive squares in 4 ways, for example, as 8949610728100 + 11471694486121 = 2991590^2 + 3386989^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20421305214221 - 2² = 20421305214217 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 (20421305214227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 116231840 + ... + 116407401.

It is an arithmetic number, because the mean of its divisors is an integer number (2616144595911).

Almost surely, 2^{20421305214221} is an apocalyptic number.

It is an amenable number.

20421305214221 is a deficient number, since it is larger than the sum of its proper divisors (507851553067).

20421305214221 is a wasteful number, since it uses less digits than its factorization.

20421305214221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 232641423.

The product of its (nonzero) digits is 7680, while the sum is 29.

Adding to 20421305214221 its reverse (12241250312402), we get a palindrome (32662555526623).

The spelling of 20421305214221 in words is "twenty trillion, four hundred twenty-one billion, three hundred five million, two hundred fourteen thousand, two hundred twenty-one".