1987789 has 2 divisors, whose sum is σ = 1987790. Its totient is φ = 1987788.

The previous prime is 1987709. The next prime is 1987819. The reversal of 1987789 is 9877891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1876900 + 110889 = 1370^2 + 333^2 .

It is a cyclic number.

It is not a de Polignac number, because 1987789 - 2⁹ = 1987277 is a prime.

1987789 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1987709) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 993894 + 993895.

It is an arithmetic number, because the mean of its divisors is an integer number (993895).

2^1987789 is an apocalyptic number.

It is an amenable number.

1987789 is a deficient number, since it is larger than the sum of its proper divisors (1).

1987789 is an equidigital number, since it uses as much as digits as its factorization.

1987789 is an evil number, because the sum of its binary digits is even.

The product of its digits is 254016, while the sum is 49.

The square root of 1987789 is about 1409.8897119988. The cubic root of 1987789 is about 125.7351664327.

The spelling of 1987789 in words is "one million, nine hundred eighty-seven thousand, seven hundred eighty-nine".