11811451081 has 16 divisors (see below), whose sum is σ = 12401305600. Its totient is φ = 11235931200.

The previous prime is 11811451079. The next prime is 11811451103. The reversal of 11811451081 is 18015411811.

It is a 7-Lehmer number, since φ(11811451081) divides (11811451081-1)⁷.

It is a cyclic number.

It is not a de Polignac number, because 11811451081 - 2¹ = 11811451079 is a prime.

It is a super-2 number, since 2×11811451081² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is the 108681-st Hogben number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11811451021) by changing a digit.

It is a nontrivial repunit in base 108680.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 550291 + ... + 571351.

It is an arithmetic number, because the mean of its divisors is an integer number (775081600).

Almost surely, 2^11811451081 is an apocalyptic number.

It is an amenable number.

11811451081 is a deficient number, since it is larger than the sum of its proper divisors (589854519).

11811451081 is a wasteful number, since it uses less digits than its factorization.

11811451081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21400.

The product of its (nonzero) digits is 1280, while the sum is 31.

Adding to 11811451081 its reverse (18015411811), we get a palindrome (29826862892).

The spelling of 11811451081 in words is "eleven billion, eight hundred eleven million, four hundred fifty-one thousand, eighty-one".