20001001022221 has 4 divisors (see below), whose sum is σ = 20008297997244. Its totient is φ = 19993704047200.

The previous prime is 20001001022203. The next prime is 20001001022269. The reversal of 20001001022221 is 12222010010002.

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 1703053710121 + 18297947312100 = 1305011^2 + 4277610^2 .

It is a cyclic number.

It is not a de Polignac number, because 20001001022221 - 2¹⁷ = 20001000891149 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 (20001001022201) 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, 3648483400 + ... + 3648488881.

It is an arithmetic number, because the mean of its divisors is an integer number (5002074499311).

Almost surely, 2^{20001001022221} is an apocalyptic number.

It is an amenable number.

20001001022221 is a deficient number, since it is larger than the sum of its proper divisors (7296975023).

20001001022221 is an equidigital number, since it uses as much as digits as its factorization.

20001001022221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7296975022.

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

Adding to 20001001022221 its reverse (12222010010002), we get a palindrome (32223011032223).

The spelling of 20001001022221 in words is "twenty trillion, one billion, one million, twenty-two thousand, two hundred twenty-one".