3813981 has 8 divisors (see below), whose sum is σ = 5103840. Its totient is φ = 2533392.

The previous prime is 3813959. The next prime is 3813983. The reversal of 3813981 is 1893183.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 3813981 - 2⁵ = 3813949 is a prime.

It is a super-2 number, since 2×3813981² = 29092902136722, which contains 22 as substring.

It is an Ulam number.

3813981 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3813983) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1291 + ... + 3048.

It is an arithmetic number, because the mean of its divisors is an integer number (637980).

Almost surely, 2^3813981 is an apocalyptic number.

It is an amenable number.

3813981 is a deficient number, since it is larger than the sum of its proper divisors (1289859).

3813981 is a wasteful number, since it uses less digits than its factorization.

3813981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4635.

The product of its digits is 5184, while the sum is 33.

The square root of 3813981 is about 1952.9416273919. The cubic root of 3813981 is about 156.2402199745.

The spelling of 3813981 in words is "three million, eight hundred thirteen thousand, nine hundred eighty-one".