181901 has 4 divisors (see below), whose sum is σ = 183804. Its totient is φ = 180000.
The previous prime is 181891. The next prime is 181903. The reversal of 181901 is 109181.
181901 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.
It is a semiprime because it is the product of two primes.
It can be written as a sum of positive squares in 2 ways, for example, as 106276 + 75625 = 326^2 + 275^2 .
It is a cyclic number.
It is not a de Polignac number, because 181901 - 26 = 181837 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 (181903) 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, 800 + ... + 1001.
It is an arithmetic number, because the mean of its divisors is an integer number (45951).
It is a Poulet number, since it divides 2181900-1.
2181901 is an apocalyptic number.
It is an amenable number.
181901 is a deficient number, since it is larger than the sum of its proper divisors (1903).
181901 is a wasteful number, since it uses less digits than its factorization.
181901 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 1902.
The product of its (nonzero) digits is 72, while the sum is 20.
The square root of 181901 is about 426.4985345813. The cubic root of 181901 is about 56.6602337949.
The spelling of 181901 in words is "one hundred eighty-one thousand, nine hundred one".
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