3861981 has 6 divisors (see below), whose sum is σ = 5578430. Its totient is φ = 2574648.

The previous prime is 3861967. The next prime is 3861983. The reversal of 3861981 is 1891683.

3861981 is a `hidden beast` number, since 38 + 619 + 8 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 2576025 + 1285956 = 1605^2 + 1134^2 .

It is not a de Polignac number, because 3861981 - 2¹⁸ = 3599837 is a prime.

It is a super-2 number, since 2×3861981² = 29829794488722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3861983) 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, 214546 + ... + 214563.

Almost surely, 2^3861981 is an apocalyptic number.

It is an amenable number.

3861981 is a deficient number, since it is larger than the sum of its proper divisors (1716449).

3861981 is a wasteful number, since it uses less digits than its factorization.

3861981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 429115 (or 429112 counting only the distinct ones).

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

The square root of 3861981 is about 1965.1923569971. The cubic root of 3861981 is about 156.8929314487.

The spelling of 3861981 in words is "three million, eight hundred sixty-one thousand, nine hundred eighty-one".