20555557011109 has 2 divisors, whose sum is σ = 20555557011110. Its totient is φ = 20555557011108.

The previous prime is 20555557011029. The next prime is 20555557011139. The reversal of 20555557011109 is 90111075555502.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14903421645025 + 5652135366084 = 3860495^2 + 2377422^2 .

It is a cyclic number.

It is not a de Polignac number, because 20555557011109 - 2¹⁷ = 20555556880037 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20555557011139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10277778505554 + 10277778505555.

It is an arithmetic number, because the mean of its divisors is an integer number (10277778505555).

Almost surely, 2^{20555557011109} is an apocalyptic number.

It is an amenable number.

20555557011109 is a deficient number, since it is larger than the sum of its proper divisors (1).

20555557011109 is an equidigital number, since it uses as much as digits as its factorization.

20555557011109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 393750, while the sum is 46.

The spelling of 20555557011109 in words is "twenty trillion, five hundred fifty-five billion, five hundred fifty-seven million, eleven thousand, one hundred nine".