3987591781 has 2 divisors, whose sum is σ = 3987591782. Its totient is φ = 3987591780.

The previous prime is 3987591701. The next prime is 3987591809. The reversal of 3987591781 is 1871957893.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3510562500 + 477029281 = 59250^2 + 21841^2 .

It is a cyclic number.

It is not a de Polignac number, because 3987591781 - 2¹¹ = 3987589733 is a prime.

It is a super-2 number, since 2×3987591781² = 31801776423797503922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3987591701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1993795890 + 1993795891.

It is an arithmetic number, because the mean of its divisors is an integer number (1993795891).

Almost surely, 2^3987591781 is an apocalyptic number.

It is an amenable number.

3987591781 is a deficient number, since it is larger than the sum of its proper divisors (1).

3987591781 is an equidigital number, since it uses as much as digits as its factorization.

3987591781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3810240, while the sum is 58.

The square root of 3987591781 is about 63147.3814263109. The cubic root of 3987591781 is about 1585.7579501401.

The spelling of 3987591781 in words is "three billion, nine hundred eighty-seven million, five hundred ninety-one thousand, seven hundred eighty-one".