61618205175581 has 2 divisors, whose sum is σ = 61618205175582. Its totient is φ = 61618205175580.

The previous prime is 61618205175557. The next prime is 61618205175601. The reversal of 61618205175581 is 18557150281616.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 49209733951225 + 12408471224356 = 7014965^2 + 3522566^2 .

It is a cyclic number.

It is not a de Polignac number, because 61618205175581 - 2³⁸ = 61343327268637 is a prime.

It is a super-2 number, since 2×61618205175581² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61618205175181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30809102587790 + 30809102587791.

It is an arithmetic number, because the mean of its divisors is an integer number (30809102587791).

Almost surely, 2^{61618205175581} is an apocalyptic number.

It is an amenable number.

61618205175581 is a deficient number, since it is larger than the sum of its proper divisors (1).

61618205175581 is an equidigital number, since it uses as much as digits as its factorization.

61618205175581 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 61618205175581 in words is "sixty-one trillion, six hundred eighteen billion, two hundred five million, one hundred seventy-five thousand, five hundred eighty-one".