202121110109 has 2 divisors, whose sum is σ = 202121110110. Its totient is φ = 202121110108.

The previous prime is 202121110069. The next prime is 202121110123. The reversal of 202121110109 is 901011121202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 174231108100 + 27890002009 = 417410^2 + 167003^2 .

It is a cyclic number.

It is not a de Polignac number, because 202121110109 - 2¹² = 202121106013 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (202141110109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 101060555054 + 101060555055.

It is an arithmetic number, because the mean of its divisors is an integer number (101060555055).

Almost surely, 2^202121110109 is an apocalyptic number.

It is an amenable number.

202121110109 is a deficient number, since it is larger than the sum of its proper divisors (1).

202121110109 is an equidigital number, since it uses as much as digits as its factorization.

202121110109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 20.

The spelling of 202121110109 in words is "two hundred two billion, one hundred twenty-one million, one hundred ten thousand, one hundred nine".