387781 has 2 divisors, whose sum is σ = 387782. Its totient is φ = 387780.

The previous prime is 387763. The next prime is 387791. The reversal of 387781 is 187783.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 370881 + 16900 = 609^2 + 130^2 .

It is a cyclic number.

It is not a de Polignac number, because 387781 - 2⁵ = 387749 is a prime.

It is a super-2 number, since 2×387781² = 300748207922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (387721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 193890 + 193891.

It is an arithmetic number, because the mean of its divisors is an integer number (193891).

2³⁸⁷⁷⁸¹ is an apocalyptic number.

It is an amenable number.

387781 is a deficient number, since it is larger than the sum of its proper divisors (1).

387781 is an equidigital number, since it uses as much as digits as its factorization.

387781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9408, while the sum is 34.

The square root of 387781 is about 622.7206436276. The cubic root of 387781 is about 72.9226051581.

The spelling of 387781 in words is "three hundred eighty-seven thousand, seven hundred eighty-one".