1988605 has 4 divisors (see below), whose sum is σ = 2386332. Its totient is φ = 1590880.

The previous prime is 1988599. The next prime is 1988611. The reversal of 1988605 is 5068891.

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

It is an interprime number because it is at equal distance from previous prime (1988599) and next prime (1988611).

It can be written as a sum of positive squares in 2 ways, for example, as 443556 + 1545049 = 666^2 + 1243^2 .

It is not a de Polignac number, because 1988605 - 2¹³ = 1980413 is a prime.

It is a Duffinian number.

1988605 is a lucky number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 198856 + ... + 198865.

It is an arithmetic number, because the mean of its divisors is an integer number (596583).

2^1988605 is an apocalyptic number.

It is an amenable number.

1988605 is a deficient number, since it is larger than the sum of its proper divisors (397727).

1988605 is an equidigital number, since it uses as much as digits as its factorization.

1988605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 397726.

The product of its (nonzero) digits is 17280, while the sum is 37.

The square root of 1988605 is about 1410.1790666437. The cubic root of 1988605 is about 125.7523691069.

The spelling of 1988605 in words is "one million, nine hundred eighty-eight thousand, six hundred five".