1987705 has 4 divisors (see below), whose sum is σ = 2385252. Its totient is φ = 1590160.

The previous prime is 1987703. The next prime is 1987709. The reversal of 1987705 is 5077891.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 300304 + 1687401 = 548^2 + 1299^2 .

It is not a de Polignac number, because 1987705 - 2¹ = 1987703 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1987703) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 198766 + ... + 198775.

It is an arithmetic number, because the mean of its divisors is an integer number (596313).

2^1987705 is an apocalyptic number.

It is an amenable number.

1987705 is a deficient number, since it is larger than the sum of its proper divisors (397547).

1987705 is an equidigital number, since it uses as much as digits as its factorization.

1987705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 397546.

The product of its (nonzero) digits is 17640, while the sum is 37.

The square root of 1987705 is about 1409.8599221199. The cubic root of 1987705 is about 125.7333953019.

The spelling of 1987705 in words is "one million, nine hundred eighty-seven thousand, seven hundred five".