1155615500861 has 2 divisors, whose sum is σ = 1155615500862. Its totient is φ = 1155615500860.

The previous prime is 1155615500737. The next prime is 1155615500881. The reversal of 1155615500861 is 1680055165511.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 819106452025 + 336509048836 = 905045^2 + 580094^2 .

It is a cyclic number.

It is not a de Polignac number, because 1155615500861 - 2²² = 1155611306557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1155615500881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 577807750430 + 577807750431.

It is an arithmetic number, because the mean of its divisors is an integer number (577807750431).

Almost surely, 2^{1155615500861} is an apocalyptic number.

It is an amenable number.

1155615500861 is a deficient number, since it is larger than the sum of its proper divisors (1).

1155615500861 is an equidigital number, since it uses as much as digits as its factorization.

1155615500861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 180000, while the sum is 44.

The spelling of 1155615500861 in words is "one trillion, one hundred fifty-five billion, six hundred fifteen million, five hundred thousand, eight hundred sixty-one".