1155661556111 has 4 divisors (see below), whose sum is σ = 1162751504472. Its totient is φ = 1148571607752.

The previous prime is 1155661556039. The next prime is 1155661556141. The reversal of 1155661556111 is 1116551665511.

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 1155661556111 - 2¹⁸ = 1155661293967 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1155661556141) 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, 3544973936 + ... + 3544974261.

It is an arithmetic number, because the mean of its divisors is an integer number (290687876118).

Almost surely, 2^{1155661556111} is an apocalyptic number.

1155661556111 is a deficient number, since it is larger than the sum of its proper divisors (7089948361).

1155661556111 is an equidigital number, since it uses as much as digits as its factorization.

1155661556111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7089948360.

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

The spelling of 1155661556111 in words is "one trillion, one hundred fifty-five billion, six hundred sixty-one million, five hundred fifty-six thousand, one hundred eleven".