1987791 has 8 divisors (see below), whose sum is σ = 2854320. Its totient is φ = 1223232.

The previous prime is 1987789. The next prime is 1987819. The reversal of 1987791 is 1977891.

It is a happy number.

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

It is not a de Polignac number, because 1987791 - 2¹ = 1987789 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1987091) 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 in 7 ways as a sum of consecutive naturals, for example, 25446 + ... + 25523.

It is an arithmetic number, because the mean of its divisors is an integer number (356790).

2^1987791 is an apocalyptic number.

1987791 is a deficient number, since it is larger than the sum of its proper divisors (866529).

1987791 is a wasteful number, since it uses less digits than its factorization.

1987791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50985.

The product of its digits is 31752, while the sum is 42.

The square root of 1987791 is about 1409.8904212739. The cubic root of 1987791 is about 125.7352086019.

The spelling of 1987791 in words is "one million, nine hundred eighty-seven thousand, seven hundred ninety-one".