201121000021 has 2 divisors, whose sum is σ = 201121000022. Its totient is φ = 201121000020.

The previous prime is 201121000019. The next prime is 201121000043. The reversal of 201121000021 is 120000121102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 194623027921 + 6497972100 = 441161^2 + 80610^2 .

It is a cyclic number.

It is not a de Polignac number, because 201121000021 - 2¹ = 201121000019 is a prime.

Together with 201121000019, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 201120999971 and 201121000007.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201121000121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100560500010 + 100560500011.

It is an arithmetic number, because the mean of its divisors is an integer number (100560500011).

Almost surely, 2^201121000021 is an apocalyptic number.

It is an amenable number.

201121000021 is a deficient number, since it is larger than the sum of its proper divisors (1).

201121000021 is an equidigital number, since it uses as much as digits as its factorization.

201121000021 is an evil number, because the sum of its binary digits is even.

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

Adding to 201121000021 its reverse (120000121102), we get a palindrome (321121121123).

The spelling of 201121000021 in words is "two hundred one billion, one hundred twenty-one million, twenty-one", and thus it is an aban number.