1161556551611 has 4 divisors (see below), whose sum is σ = 1199026117824. Its totient is φ = 1124086985400.

The previous prime is 1161556551607. The next prime is 1161556551613.

1161556551611 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1161556551611 - 2² = 1161556551607 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1161556551613) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18734783060 + ... + 18734783121.

It is an arithmetic number, because the mean of its divisors is an integer number (299756529456).

Almost surely, 2^{1161556551611} is an apocalyptic number.

1161556551611 is a deficient number, since it is larger than the sum of its proper divisors (37469566213).

1161556551611 is an equidigital number, since it uses as much as digits as its factorization.

1161556551611 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37469566212.

The product of its digits is 135000, while the sum is 44.

The spelling of 1161556551611 in words is "one trillion, one hundred sixty-one billion, five hundred fifty-six million, five hundred fifty-one thousand, six hundred eleven".