1181551811 has 12 divisors (see below), whose sum is σ = 1299568536. Its totient is φ = 1073445120.

The previous prime is 1181551783. The next prime is 1181551853.

1181551811 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1181551811 - 2¹⁴ = 1181535427 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1181551411) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 331340 + ... + 334886.

It is an arithmetic number, because the mean of its divisors is an integer number (108297378).

Almost surely, 2^1181551811 is an apocalyptic number.

1181551811 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1181551811 is a deficient number, since it is larger than the sum of its proper divisors (118016725).

1181551811 is a wasteful number, since it uses less digits than its factorization.

1181551811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6322 (or 6311 counting only the distinct ones).

The product of its digits is 1600, while the sum is 32.

The square root of 1181551811 is about 34373.7081357249. The cubic root of 1181551811 is about 1057.1848318693.

The spelling of 1181551811 in words is "one billion, one hundred eighty-one million, five hundred fifty-one thousand, eight hundred eleven".