1161555511 has 2 divisors, whose sum is σ = 1161555512. Its totient is φ = 1161555510.

The previous prime is 1161555491. The next prime is 1161555533. The reversal of 1161555511 is 1155551611.

It is a weak prime.

It is an emirp because it is prime and its reverse (1155551611) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1161555511 - 2¹³ = 1161547319 is a prime.

It is a super-2 number, since 2×1161555511² = 2698422410268942242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1161555581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 580777755 + 580777756.

It is an arithmetic number, because the mean of its divisors is an integer number (580777756).

Almost surely, 2^1161555511 is an apocalyptic number.

1161555511 is a deficient number, since it is larger than the sum of its proper divisors (1).

1161555511 is an equidigital number, since it uses as much as digits as its factorization.

1161555511 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3750, while the sum is 31.

The square root of 1161555511 is about 34081.6007693301. The cubic root of 1161555511 is about 1051.1870206864.

The spelling of 1161555511 in words is "one billion, one hundred sixty-one million, five hundred fifty-five thousand, five hundred eleven".