3981618 has 12 divisors (see below), whose sum is σ = 8626878. Its totient is φ = 1327200.

The previous prime is 3981617. The next prime is 3981619. The reversal of 3981618 is 8161893.

3981618 is a `hidden beast` number, since 39 + 8 + 1 + 618 = 666.

It is an interprime number because it is at equal distance from previous prime (3981617) and next prime (3981619).

It can be written as a sum of positive squares in only one way, i.e., 3122289 + 859329 = 1767^2 + 927^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (3981617) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 110583 + ... + 110618.

Almost surely, 2^3981618 is an apocalyptic number.

3981618 is an abundant number, since it is smaller than the sum of its proper divisors (4645260).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

3981618 is a wasteful number, since it uses less digits than its factorization.

3981618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221209 (or 221206 counting only the distinct ones).

The product of its digits is 10368, while the sum is 36.

The square root of 3981618 is about 1995.3992081787. The cubic root of 3981618 is about 158.4965683727.

It can be divided in two parts, 398 and 1618, that added together give a triangular number (2016 = T₆₃).

The spelling of 3981618 in words is "three million, nine hundred eighty-one thousand, six hundred eighteen".