1987399 has 4 divisors (see below), whose sum is σ = 2055960. Its totient is φ = 1918840.

The previous prime is 1987373. The next prime is 1987411. The reversal of 1987399 is 9937891.

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

It is a cyclic number.

It is not a de Polignac number, because 1987399 - 2¹³ = 1979207 is a prime.

It is a Duffinian number.

1987399 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1987309) 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, 34237 + ... + 34294.

It is an arithmetic number, because the mean of its divisors is an integer number (513990).

2^1987399 is an apocalyptic number.

1987399 is a deficient number, since it is larger than the sum of its proper divisors (68561).

1987399 is an equidigital number, since it uses as much as digits as its factorization.

1987399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68560.

The product of its digits is 122472, while the sum is 46.

The square root of 1987399 is about 1409.7513965235. The cubic root of 1987399 is about 125.7269429036.

The spelling of 1987399 in words is "one million, nine hundred eighty-seven thousand, three hundred ninety-nine".