21002020002109 has 2 divisors, whose sum is σ = 21002020002110. Its totient is φ = 21002020002108.

The previous prime is 21002020002101. The next prime is 21002020002133. The reversal of 21002020002109 is 90120002020012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20532045312900 + 469974689209 = 4531230^2 + 685547^2 .

It is a cyclic number.

It is not a de Polignac number, because 21002020002109 - 2³ = 21002020002101 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21002020002101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501010001054 + 10501010001055.

It is an arithmetic number, because the mean of its divisors is an integer number (10501010001055).

Almost surely, 2^{21002020002109} is an apocalyptic number.

It is an amenable number.

21002020002109 is a deficient number, since it is larger than the sum of its proper divisors (1).

21002020002109 is an equidigital number, since it uses as much as digits as its factorization.

21002020002109 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 19.

The spelling of 21002020002109 in words is "twenty-one trillion, two billion, twenty million, two thousand, one hundred nine".