20021210102009 has 2 divisors, whose sum is σ = 20021210102010. Its totient is φ = 20021210102008.

The previous prime is 20021210101939. The next prime is 20021210102029. The reversal of 20021210102009 is 90020101212002.

It is a happy number.

It is an a-pointer prime, because the next prime (20021210102029) can be obtained adding 20021210102009 to its sum of digits (20).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17612962368400 + 2408247733609 = 4196780^2 + 1551853^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20021210102009 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (20021210102029) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10010605051004 + 10010605051005.

It is an arithmetic number, because the mean of its divisors is an integer number (10010605051005).

Almost surely, 2^{20021210102009} is an apocalyptic number.

It is an amenable number.

20021210102009 is a deficient number, since it is larger than the sum of its proper divisors (1).

20021210102009 is an equidigital number, since it uses as much as digits as its factorization.

20021210102009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144, while the sum is 20.

The spelling of 20021210102009 in words is "twenty trillion, twenty-one billion, two hundred ten million, one hundred two thousand, nine".