20011001221 has 4 divisors (see below), whose sum is σ = 20198020032. Its totient is φ = 19823982412.

The previous prime is 20011001173. The next prime is 20011001249. The reversal of 20011001221 is 12210011002.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20011001221 - 2⁷ = 20011001093 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20011001198 and 20011001207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20012001221) 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, 93509245 + ... + 93509458.

It is an arithmetic number, because the mean of its divisors is an integer number (5049505008).

Almost surely, 2^20011001221 is an apocalyptic number.

It is an amenable number.

20011001221 is a deficient number, since it is larger than the sum of its proper divisors (187018811).

20011001221 is a wasteful number, since it uses less digits than its factorization.

20011001221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187018810.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 20011001221 its reverse (12210011002), we get a palindrome (32221012223).

The spelling of 20011001221 in words is "twenty billion, eleven million, one thousand, two hundred twenty-one".