20351611551809 has 2 divisors, whose sum is σ = 20351611551810. Its totient is φ = 20351611551808.

The previous prime is 20351611551787. The next prime is 20351611551851. The reversal of 20351611551809 is 90815511615302.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19902305440000 + 449306111809 = 4461200^2 + 670303^2 .

It is a cyclic number.

It is not a de Polignac number, because 20351611551809 - 2⁸ = 20351611551553 is a prime.

It is not a weakly prime, because it can be changed into another prime (20351611551889) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10175805775904 + 10175805775905.

It is an arithmetic number, because the mean of its divisors is an integer number (10175805775905).

Almost surely, 2^{20351611551809} is an apocalyptic number.

It is an amenable number.

20351611551809 is a deficient number, since it is larger than the sum of its proper divisors (1).

20351611551809 is an equidigital number, since it uses as much as digits as its factorization.

20351611551809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 324000, while the sum is 47.

The spelling of 20351611551809 in words is "twenty trillion, three hundred fifty-one billion, six hundred eleven million, five hundred fifty-one thousand, eight hundred nine".