1861181 has 4 divisors (see below), whose sum is σ = 2127072. Its totient is φ = 1595292.

The previous prime is 1861157. The next prime is 1861187. The reversal of 1861181 is 1811681.

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 a de Polignac number, because none of the positive numbers 2^k-1861181 is a prime.

It is a super-2 number, since 2×1861181² = 6927989429522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1861181.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1861187) 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, 132935 + ... + 132948.

It is an arithmetic number, because the mean of its divisors is an integer number (531768).

2^1861181 is an apocalyptic number.

It is an amenable number.

1861181 is a deficient number, since it is larger than the sum of its proper divisors (265891).

1861181 is an equidigital number, since it uses as much as digits as its factorization.

1861181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 265890.

The product of its digits is 384, while the sum is 26.

The square root of 1861181 is about 1364.2510765984. The cubic root of 1861181 is about 123.0069178915.

The spelling of 1861181 in words is "one million, eight hundred sixty-one thousand, one hundred eighty-one".