18811881 has 48 divisors (see below), whose sum is σ = 31861440. Its totient is φ = 10575360.

The previous prime is 18811879. The next prime is 18811883.

18811881 is nontrivially palindromic in base 10.

It is an interprime number because it is at equal distance from previous prime (18811879) and next prime (18811883).

It is not a de Polignac number, because 18811881 - 2¹ = 18811879 is a prime.

It is a super-2 number, since 2×18811881² = 707773733516322, which contains 22 as substring.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

18811881 is a strobogrammatic number because it is the same when read upside-down.

It is not an unprimeable number, because it can be changed into a prime (18811883) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 137245 + ... + 137381.

It is an arithmetic number, because the mean of its divisors is an integer number (663780).

Almost surely, 2^18811881 is an apocalyptic number.

18811881 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18811881 is a deficient number, since it is larger than the sum of its proper divisors (13049559).

18811881 is a wasteful number, since it uses less digits than its factorization.

18811881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 246 (or 243 counting only the distinct ones).

The product of its digits is 4096, while the sum is 36.

The square root of 18811881 is about 4337.2665355037. The cubic root of 18811881 is about 265.9565808114.

The spelling of 18811881 in words is "eighteen million, eight hundred eleven thousand, eight hundred eighty-one".