55661812018157 has 2 divisors, whose sum is σ = 55661812018158. Its totient is φ = 55661812018156.

The previous prime is 55661812018097. The next prime is 55661812018199. The reversal of 55661812018157 is 75181021816655.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 51922098078601 + 3739713939556 = 7205699^2 + 1933834^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55661812018157 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55661812015157) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27830906009078 + 27830906009079.

It is an arithmetic number, because the mean of its divisors is an integer number (27830906009079).

Almost surely, 2^{55661812018157} is an apocalyptic number.

It is an amenable number.

55661812018157 is a deficient number, since it is larger than the sum of its proper divisors (1).

55661812018157 is an equidigital number, since it uses as much as digits as its factorization.

55661812018157 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4032000, while the sum is 56.

The spelling of 55661812018157 in words is "fifty-five trillion, six hundred sixty-one billion, eight hundred twelve million, eighteen thousand, one hundred fifty-seven".