1987305 has 24 divisors (see below), whose sum is σ = 3364992. Its totient is φ = 1001376.

The previous prime is 1987303. The next prime is 1987309. The reversal of 1987305 is 5037891.

It is not a de Polignac number, because 1987305 - 2¹ = 1987303 is a prime.

It is an Ulam number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1987303) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5232 + ... + 5598.

It is an arithmetic number, because the mean of its divisors is an integer number (140208).

2^1987305 is an apocalyptic number.

1987305 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1987305 is a deficient number, since it is larger than the sum of its proper divisors (1377687).

1987305 is a wasteful number, since it uses less digits than its factorization.

1987305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 413 (or 394 counting only the distinct ones).

The product of its (nonzero) digits is 7560, while the sum is 33.

The square root of 1987305 is about 1409.7180569178. The cubic root of 1987305 is about 125.7249606613.

It can be divided in two parts, 198 and 7305, that added together give a triangular number (7503 = T₁₂₂).

The spelling of 1987305 in words is "one million, nine hundred eighty-seven thousand, three hundred five".