3961781 has 2 divisors, whose sum is σ = 3961782. Its totient is φ = 3961780.

The previous prime is 3961759. The next prime is 3961813. The reversal of 3961781 is 1871693.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3960100 + 1681 = 1990^2 + 41^2 .

It is an emirp because it is prime and its reverse (1871693) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3961781 - 2¹⁰ = 3960757 is a prime.

It is a super-2 number, since 2×3961781² = 31391417383922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3961721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1980890 + 1980891.

It is an arithmetic number, because the mean of its divisors is an integer number (1980891).

Almost surely, 2^3961781 is an apocalyptic number.

It is an amenable number.

3961781 is a deficient number, since it is larger than the sum of its proper divisors (1).

3961781 is an equidigital number, since it uses as much as digits as its factorization.

3961781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9072, while the sum is 35.

The square root of 3961781 is about 1990.4223169971. The cubic root of 3961781 is about 158.2329123769.

The spelling of 3961781 in words is "three million, nine hundred sixty-one thousand, seven hundred eighty-one".