20511409819 has 2 divisors, whose sum is σ = 20511409820. Its totient is φ = 20511409818.

The previous prime is 20511409817. The next prime is 20511409843. The reversal of 20511409819 is 91890411502.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20511409819 - 2¹ = 20511409817 is a prime.

It is a super-2 number, since 2×20511409819² (a number of 21 digits) contains 22 as substring.

Together with 20511409817, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (20511409817) 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, 10255704909 + 10255704910.

It is an arithmetic number, because the mean of its divisors is an integer number (10255704910).

Almost surely, 2^20511409819 is an apocalyptic number.

20511409819 is a deficient number, since it is larger than the sum of its proper divisors (1).

20511409819 is an equidigital number, since it uses as much as digits as its factorization.

20511409819 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 40.

The spelling of 20511409819 in words is "twenty billion, five hundred eleven million, four hundred nine thousand, eight hundred nineteen".