3861661 has 4 divisors (see below), whose sum is σ = 3943872. Its totient is φ = 3779452.

The previous prime is 3861659. The next prime is 3861709. The reversal of 3861661 is 1661683.

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 3861661 - 2¹ = 3861659 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3861461) 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, 41035 + ... + 41128.

It is an arithmetic number, because the mean of its divisors is an integer number (985968).

Almost surely, 2^3861661 is an apocalyptic number.

It is an amenable number.

3861661 is a deficient number, since it is larger than the sum of its proper divisors (82211).

3861661 is an equidigital number, since it uses as much as digits as its factorization.

3861661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82210.

The product of its digits is 5184, while the sum is 31.

The square root of 3861661 is about 1965.1109383442. The cubic root of 3861661 is about 156.8885979970. Note that the first 3 decimals are identical.

It can be divided in two parts, 386 and 1661, that multiplied together give a palindrome (641146).

The spelling of 3861661 in words is "three million, eight hundred sixty-one thousand, six hundred sixty-one".