1987591 has 8 divisors (see below), whose sum is σ = 2096640. Its totient is φ = 1880472.

The previous prime is 1987577. The next prime is 1987619. The reversal of 1987591 is 1957891.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1987591 - 2¹³ = 1979399 is a prime.

It is a Duffinian number.

1987591 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1987501) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1950 + ... + 2788.

It is an arithmetic number, because the mean of its divisors is an integer number (262080).

2^1987591 is an apocalyptic number.

1987591 is a deficient number, since it is larger than the sum of its proper divisors (109049).

1987591 is a wasteful number, since it uses less digits than its factorization.

1987591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 965.

The product of its digits is 22680, while the sum is 40.

The square root of 1987591 is about 1409.8194919918. The cubic root of 1987591 is about 125.7309915447.

The spelling of 1987591 in words is "one million, nine hundred eighty-seven thousand, five hundred ninety-one".