20012221001 has 4 divisors (see below), whose sum is σ = 20021802900. Its totient is φ = 20002639104.

The previous prime is 20012220983. The next prime is 20012221063. The reversal of 20012221001 is 10012221002.

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 19335180601 + 677040400 = 139051^2 + 26020^2 .

It is a cyclic number.

It is not a de Polignac number, because 20012221001 - 2⁶ = 20012220937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20012221091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4787816 + ... + 4791993.

It is an arithmetic number, because the mean of its divisors is an integer number (5005450725).

Almost surely, 2^20012221001 is an apocalyptic number.

It is an amenable number.

20012221001 is a deficient number, since it is larger than the sum of its proper divisors (9581899).

20012221001 is an equidigital number, since it uses as much as digits as its factorization.

20012221001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9581898.

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 20012221001 its reverse (10012221002), we get a palindrome (30024442003).

Subtracting from 20012221001 its reverse (10012221002), we obtain a palindrome (9999999999).

The spelling of 20012221001 in words is "twenty billion, twelve million, two hundred twenty-one thousand, one".