1987649217 has 6 divisors (see below), whose sum is σ = 2871048882. Its totient is φ = 1325099472.

The previous prime is 1987649207. The next prime is 1987649219. The reversal of 1987649217 is 7129467891.

It can be written as a sum of positive squares in only one way, i.e., 1152670401 + 834978816 = 33951^2 + 28896^2 .

It is not a de Polignac number, because 1987649217 - 2⁸ = 1987648961 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1987649219) by changing a digit.

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, 110424948 + ... + 110424965.

It is an arithmetic number, because the mean of its divisors is an integer number (478508147).

Almost surely, 2^1987649217 is an apocalyptic number.

It is an amenable number.

1987649217 is a deficient number, since it is larger than the sum of its proper divisors (883399665).

1987649217 is a wasteful number, since it uses less digits than its factorization.

1987649217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220849919 (or 220849916 counting only the distinct ones).

The product of its digits is 1524096, while the sum is 54.

The square root of 1987649217 is about 44583.0597536777. The cubic root of 1987649217 is about 1257.3221909595.

The spelling of 1987649217 in words is "one billion, nine hundred eighty-seven million, six hundred forty-nine thousand, two hundred seventeen".