3631781 has 2 divisors, whose sum is σ = 3631782. Its totient is φ = 3631780.

The previous prime is 3631763. The next prime is 3631783. The reversal of 3631781 is 1871363.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3045025 + 586756 = 1745^2 + 766^2 .

It is a cyclic number.

It is not a de Polignac number, because 3631781 - 2¹⁸ = 3369637 is a prime.

It is a super-2 number, since 2×3631781² = 26379666463922, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 3631783, it forms a pair of twin primes.

It is a Chen 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 (3631783) 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, 1815890 + 1815891.

It is an arithmetic number, because the mean of its divisors is an integer number (1815891).

Almost surely, 2^3631781 is an apocalyptic number.

It is an amenable number.

3631781 is a deficient number, since it is larger than the sum of its proper divisors (1).

3631781 is an equidigital number, since it uses as much as digits as its factorization.

3631781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 29.

The square root of 3631781 is about 1905.7232222965. The cubic root of 3631781 is about 153.7115672771.

The spelling of 3631781 in words is "three million, six hundred thirty-one thousand, seven hundred eighty-one".