20021210123221 has 8 divisors (see below), whose sum is σ = 20059189040024. Its totient is φ = 19983242557440.

The previous prime is 20021210123183. The next prime is 20021210123273. The reversal of 20021210123221 is 12232101212002.

It can be written as a sum of positive squares in 4 ways, for example, as 8216392280625 + 11804817842596 = 2866425^2 + 3435814^2 .

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 20021210123221 - 2²³ = 20021201734613 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 (20021210126221) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 697411 + ... + 6366223.

It is an arithmetic number, because the mean of its divisors is an integer number (2507398630003).

Almost surely, 2^{20021210123221} is an apocalyptic number.

It is an amenable number.

20021210123221 is a deficient number, since it is larger than the sum of its proper divisors (37978916803).

20021210123221 is an equidigital number, since it uses as much as digits as its factorization.

20021210123221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5675511.

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

Adding to 20021210123221 its reverse (12232101212002), we get a palindrome (32253311335223).

The spelling of 20021210123221 in words is "twenty trillion, twenty-one billion, two hundred ten million, one hundred twenty-three thousand, two hundred twenty-one".