3781861 has 4 divisors (see below), whose sum is σ = 3912300. Its totient is φ = 3651424.

The previous prime is 3781859. The next prime is 3781873. The reversal of 3781861 is 1681873.

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 2356225 + 1425636 = 1535^2 + 1194^2 .

It is a cyclic number.

It is not a de Polignac number, because 3781861 - 2¹ = 3781859 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 (3781801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 65176 + ... + 65233.

It is an arithmetic number, because the mean of its divisors is an integer number (978075).

Almost surely, 2^3781861 is an apocalyptic number.

It is an amenable number.

3781861 is a deficient number, since it is larger than the sum of its proper divisors (130439).

3781861 is a wasteful number, since it uses less digits than its factorization.

3781861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130438.

The product of its digits is 8064, while the sum is 34.

The square root of 3781861 is about 1944.7007481872. The cubic root of 3781861 is about 155.8003829659.

The spelling of 3781861 in words is "three million, seven hundred eighty-one thousand, eight hundred sixty-one".