20121002221 has 2 divisors, whose sum is σ = 20121002222. Its totient is φ = 20121002220.

The previous prime is 20121002219. The next prime is 20121002327. The reversal of 20121002221 is 12220012102.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17197437321 + 2923564900 = 131139^2 + 54070^2 .

It is a cyclic number.

It is not a de Polignac number, because 20121002221 - 2¹ = 20121002219 is a prime.

Together with 20121002219, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20121002201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10060501110 + 10060501111.

It is an arithmetic number, because the mean of its divisors is an integer number (10060501111).

Almost surely, 2^20121002221 is an apocalyptic number.

It is an amenable number.

20121002221 is a deficient number, since it is larger than the sum of its proper divisors (1).

20121002221 is an equidigital number, since it uses as much as digits as its factorization.

20121002221 is an evil number, because the sum of its binary digits is even.

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

Adding to 20121002221 its reverse (12220012102), we get a palindrome (32341014323).

The spelling of 20121002221 in words is "twenty billion, one hundred twenty-one million, two thousand, two hundred twenty-one".