1987819 has 2 divisors, whose sum is σ = 1987820. Its totient is φ = 1987818.

The previous prime is 1987789. The next prime is 1987829. The reversal of 1987819 is 9187891.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1987819 - 2¹¹ = 1985771 is a prime.

It is a super-2 number, since 2×1987819² = 7902848753522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1987829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 993909 + 993910.

It is an arithmetic number, because the mean of its divisors is an integer number (993910).

2^1987819 is an apocalyptic number.

1987819 is a deficient number, since it is larger than the sum of its proper divisors (1).

1987819 is an equidigital number, since it uses as much as digits as its factorization.

1987819 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36288, while the sum is 43.

The square root of 1987819 is about 1409.9003510887. The cubic root of 1987819 is about 125.7357989673.

The spelling of 1987819 in words is "one million, nine hundred eighty-seven thousand, eight hundred nineteen".