20021222122021 has 8 divisors (see below), whose sum is σ = 20509622883288. Its totient is φ = 19532825088000.

The previous prime is 20021222122009. The next prime is 20021222122087. The reversal of 20021222122021 is 12022122212002.

It can be written as a sum of positive squares in 4 ways, for example, as 8749255231396 + 11271966890625 = 2957914^2 + 3357375^2 .

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

It is not a de Polignac number, because 20021222122021 - 2²³ = 20021213733413 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20021222122021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021222122921) 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, 12158181 + ... + 13706341.

It is an arithmetic number, because the mean of its divisors is an integer number (2563702860411).

Almost surely, 2^{20021222122021} is an apocalyptic number.

It is an amenable number.

20021222122021 is a deficient number, since it is larger than the sum of its proper divisors (488400761267).

20021222122021 is a wasteful number, since it uses less digits than its factorization.

20021222122021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1863623.

The product of its (nonzero) digits is 256, while the sum is 19.

Adding to 20021222122021 its reverse (12022122212002), we get a palindrome (32043344334023).

The spelling of 20021222122021 in words is "twenty trillion, twenty-one billion, two hundred twenty-two million, one hundred twenty-two thousand, twenty-one".