181405881 has 12 divisors (see below), whose sum is σ = 262220608. Its totient is φ = 120849624.

The previous prime is 181405867. The next prime is 181405891. The reversal of 181405881 is 188504181.

It is a happy number.

It is not a de Polignac number, because 181405881 - 2¹⁰ = 181404857 is a prime.

It is a super-2 number, since 2×181405881² = 65816187322772322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (181405841) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 7356 + ... + 20418.

Almost surely, 2^181405881 is an apocalyptic number.

It is an amenable number.

181405881 is a deficient number, since it is larger than the sum of its proper divisors (80814727).

181405881 is a wasteful number, since it uses less digits than its factorization.

181405881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14612 (or 14609 counting only the distinct ones).

The product of its (nonzero) digits is 10240, while the sum is 36.

The square root of 181405881 is about 13468.7000486313. The cubic root of 181405881 is about 566.0877897430.

The spelling of 181405881 in words is "one hundred eighty-one million, four hundred five thousand, eight hundred eighty-one".