181306861 has 4 divisors (see below), whose sum is σ = 189189792. Its totient is φ = 173423932.

The previous prime is 181306849. The next prime is 181306889. The reversal of 181306861 is 168603181.

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 181306861 - 2⁷ = 181306733 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (181306061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3941431 + ... + 3941476.

It is an arithmetic number, because the mean of its divisors is an integer number (47297448).

Almost surely, 2^181306861 is an apocalyptic number.

It is an amenable number.

181306861 is a deficient number, since it is larger than the sum of its proper divisors (7882931).

181306861 is an equidigital number, since it uses as much as digits as its factorization.

181306861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7882930.

The product of its (nonzero) digits is 6912, while the sum is 34.

The square root of 181306861 is about 13465.0236167635. The cubic root of 181306861 is about 565.9847717396.

The spelling of 181306861 in words is "one hundred eighty-one million, three hundred six thousand, eight hundred sixty-one".