111515638056661 has 2 divisors, whose sum is σ = 111515638056662. Its totient is φ = 111515638056660.

The previous prime is 111515638056643. The next prime is 111515638056671. The reversal of 111515638056661 is 166650836515111.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 104858624002500 + 6657014054161 = 10240050^2 + 2580119^2 .

It is a cyclic number.

It is not a de Polignac number, because 111515638056661 - 2¹⁷ = 111515637925589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111515638056671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55757819028330 + 55757819028331.

It is an arithmetic number, because the mean of its divisors is an integer number (55757819028331).

Almost surely, 2^{111515638056661} is an apocalyptic number.

It is an amenable number.

111515638056661 is a deficient number, since it is larger than the sum of its proper divisors (1).

111515638056661 is an equidigital number, since it uses as much as digits as its factorization.

111515638056661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888000, while the sum is 55.

The spelling of 111515638056661 in words is "one hundred eleven trillion, five hundred fifteen billion, six hundred thirty-eight million, fifty-six thousand, six hundred sixty-one".