20121100221 has 16 divisors (see below), whose sum is σ = 26933062464. Its totient is φ = 13361649024.

The previous prime is 20121100217. The next prime is 20121100267. The reversal of 20121100221 is 12200112102.

It is not a de Polignac number, because 20121100221 - 2² = 20121100217 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20121100197 and 20121100206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121100211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2295970 + ... + 2304716.

It is an arithmetic number, because the mean of its divisors is an integer number (1683316404).

Almost surely, 2^20121100221 is an apocalyptic number.

It is an amenable number.

20121100221 is a deficient number, since it is larger than the sum of its proper divisors (6811962243).

20121100221 is a wasteful number, since it uses less digits than its factorization.

20121100221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11660.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 20121100221 its reverse (12200112102), we get a palindrome (32321212323).

The spelling of 20121100221 in words is "twenty billion, one hundred twenty-one million, one hundred thousand, two hundred twenty-one".