20081955557 has 2 divisors, whose sum is σ = 20081955558. Its totient is φ = 20081955556.

The previous prime is 20081955539. The next prime is 20081955571. The reversal of 20081955557 is 75555918002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11632485316 + 8449470241 = 107854^2 + 91921^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20081955557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20081955457) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10040977778 + 10040977779.

It is an arithmetic number, because the mean of its divisors is an integer number (10040977779).

Almost surely, 2^20081955557 is an apocalyptic number.

It is an amenable number.

20081955557 is a deficient number, since it is larger than the sum of its proper divisors (1).

20081955557 is an equidigital number, since it uses as much as digits as its factorization.

20081955557 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 630000, while the sum is 47.

The spelling of 20081955557 in words is "twenty billion, eighty-one million, nine hundred fifty-five thousand, five hundred fifty-seven".