1987780775 has 6 divisors (see below), whose sum is σ = 2464848192. Its totient is φ = 1590224600.

The previous prime is 1987780763. The next prime is 1987780867. The reversal of 1987780775 is 5770877891.

It is not a de Polignac number, because 1987780775 - 2¹⁶ = 1987715239 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 39755591 + ... + 39755640.

It is an arithmetic number, because the mean of its divisors is an integer number (410808032).

Almost surely, 2^1987780775 is an apocalyptic number.

1987780775 is a deficient number, since it is larger than the sum of its proper divisors (477067417).

1987780775 is an equidigital number, since it uses as much as digits as its factorization.

1987780775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79511241 (or 79511236 counting only the distinct ones).

The product of its (nonzero) digits is 6914880, while the sum is 59.

The square root of 1987780775 is about 44584.5351551410. The cubic root of 1987780775 is about 1257.3499301170.

The spelling of 1987780775 in words is "one billion, nine hundred eighty-seven million, seven hundred eighty thousand, seven hundred seventy-five".