3817981 has 2 divisors, whose sum is σ = 3817982. Its totient is φ = 3817980.

The previous prime is 3817969. The next prime is 3817987. The reversal of 3817981 is 1897183.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2295225 + 1522756 = 1515^2 + 1234^2 .

It is a cyclic number.

It is not a de Polignac number, because 3817981 - 2¹⁵ = 3785213 is a prime.

It is a super-2 number, since 2×3817981² = 29153957832722, which contains 22 as substring.

3817981 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 3817981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3817987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1908990 + 1908991.

It is an arithmetic number, because the mean of its divisors is an integer number (1908991).

Almost surely, 2^3817981 is an apocalyptic number.

It is an amenable number.

3817981 is a deficient number, since it is larger than the sum of its proper divisors (1).

3817981 is an equidigital number, since it uses as much as digits as its factorization.

3817981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12096, while the sum is 37.

The square root of 3817981 is about 1953.9654551706. The cubic root of 3817981 is about 156.2948210616.

The spelling of 3817981 in words is "three million, eight hundred seventeen thousand, nine hundred eighty-one".