3981815 has 4 divisors (see below), whose sum is σ = 4778184. Its totient is φ = 3185448.

The previous prime is 3981767. The next prime is 3981821. The reversal of 3981815 is 5181893.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 3981815 - 2¹² = 3977719 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 398177 + ... + 398186.

It is an arithmetic number, because the mean of its divisors is an integer number (1194546).

Almost surely, 2^3981815 is an apocalyptic number.

3981815 is a deficient number, since it is larger than the sum of its proper divisors (796369).

3981815 is an equidigital number, since it uses as much as digits as its factorization.

3981815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 796368.

The product of its digits is 8640, while the sum is 35.

The square root of 3981815 is about 1995.4485711238. The cubic root of 3981815 is about 158.4991823275.

The spelling of 3981815 in words is "three million, nine hundred eighty-one thousand, eight hundred fifteen".