20611556057 has 2 divisors, whose sum is σ = 20611556058. Its totient is φ = 20611556056.

The previous prime is 20611556051. The next prime is 20611556081. The reversal of 20611556057 is 75065511602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20158036441 + 453519616 = 141979^2 + 21296^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20611556057 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20611556057.

It is not a weakly prime, because it can be changed into another prime (20611556051) 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, 10305778028 + 10305778029.

It is an arithmetic number, because the mean of its divisors is an integer number (10305778029).

Almost surely, 2^20611556057 is an apocalyptic number.

It is an amenable number.

20611556057 is a deficient number, since it is larger than the sum of its proper divisors (1).

20611556057 is an equidigital number, since it uses as much as digits as its factorization.

20611556057 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 63000, while the sum is 38.

The spelling of 20611556057 in words is "twenty billion, six hundred eleven million, five hundred fifty-six thousand, fifty-seven".