1987090009 has 2 divisors, whose sum is σ = 1987090010. Its totient is φ = 1987090008.

The previous prime is 1987089997. The next prime is 1987090019. The reversal of 1987090009 is 9000907891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1982742784 + 4347225 = 44528^2 + 2085^2 .

It is a cyclic number.

It is not a de Polignac number, because 1987090009 - 2¹¹ = 1987087961 is a prime.

It is not a weakly prime, because it can be changed into another prime (1987090019) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 993545004 + 993545005.

It is an arithmetic number, because the mean of its divisors is an integer number (993545005).

Almost surely, 2^1987090009 is an apocalyptic number.

It is an amenable number.

1987090009 is a deficient number, since it is larger than the sum of its proper divisors (1).

1987090009 is an equidigital number, since it uses as much as digits as its factorization.

1987090009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 40824, while the sum is 43.

The square root of 1987090009 is about 44576.7877824322. The cubic root of 1987090009 is about 1257.2042676410.

The spelling of 1987090009 in words is "one billion, nine hundred eighty-seven million, ninety thousand, nine".