181863681 has 4 divisors (see below), whose sum is σ = 242484912. Its totient is φ = 121242452.

The previous prime is 181863677. The next prime is 181863683. The reversal of 181863681 is 186368181.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 181863681 - 2² = 181863677 is a prime.

It is a super-2 number, since 2×181863681² = 66148796933739522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (181863683) 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 3 ways as a sum of consecutive naturals, for example, 30310611 + ... + 30310616.

It is an arithmetic number, because the mean of its divisors is an integer number (60621228).

Almost surely, 2^181863681 is an apocalyptic number.

It is an amenable number.

181863681 is a deficient number, since it is larger than the sum of its proper divisors (60621231).

181863681 is an equidigital number, since it uses as much as digits as its factorization.

181863681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60621230.

The product of its digits is 55296, while the sum is 42.

The square root of 181863681 is about 13485.6842985441. The cubic root of 181863681 is about 566.5635870559.

The spelling of 181863681 in words is "one hundred eighty-one million, eight hundred sixty-three thousand, six hundred eighty-one".