3881781 has 12 divisors (see below), whose sum is σ = 5759052. Its totient is φ = 2517696.

The previous prime is 3881743. The next prime is 3881803. The reversal of 3881781 is 1871883.

It can be written as a sum of positive squares in 2 ways, for example, as 3186225 + 695556 = 1785^2 + 834^2 .

It is not a de Polignac number, because 3881781 - 2¹⁰ = 3880757 is a prime.

It is a super-2 number, since 2×3881781² = 30136447463922, which contains 22 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3881711) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5496 + ... + 6161.

It is an arithmetic number, because the mean of its divisors is an integer number (479921).

Almost surely, 2^3881781 is an apocalyptic number.

It is an amenable number.

3881781 is a deficient number, since it is larger than the sum of its proper divisors (1877271).

3881781 is a wasteful number, since it uses less digits than its factorization.

3881781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11700 (or 11697 counting only the distinct ones).

The product of its digits is 10752, while the sum is 36.

The square root of 3881781 is about 1970.2235913723. The cubic root of 3881781 is about 157.1605994528.

The spelling of 3881781 in words is "three million, eight hundred eighty-one thousand, seven hundred eighty-one".