11661881 has 32 divisors (see below), whose sum is σ = 15759360. Its totient is φ = 8352000.

The previous prime is 11661863. The next prime is 11661893. The reversal of 11661881 is 18816611.

It is a cyclic number.

It is not a de Polignac number, because 11661881 - 2¹⁴ = 11645497 is a prime.

It is a super-2 number, since 2×11661881² = 271998936916322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11661841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 77156 + ... + 77306.

It is an arithmetic number, because the mean of its divisors is an integer number (492480).

Almost surely, 2^11661881 is an apocalyptic number.

11661881 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

11661881 is a deficient number, since it is larger than the sum of its proper divisors (4097479).

11661881 is a wasteful number, since it uses less digits than its factorization.

11661881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 245.

The product of its digits is 2304, while the sum is 32.

The square root of 11661881 is about 3414.9496335964. The cubic root of 11661881 is about 226.7720547507.

The spelling of 11661881 in words is "eleven million, six hundred sixty-one thousand, eight hundred eighty-one".