1989987 has 8 divisors (see below), whose sum is σ = 2661120. Its totient is φ = 1322760.

The previous prime is 1989979. The next prime is 1989989. The reversal of 1989987 is 7899891.

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

It is not a de Polignac number, because 1989987 - 2³ = 1989979 is a prime.

It is a super-3 number, since 3×1989987³ = 23641333671326783409, which contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (1989989) 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, 562 + ... + 2072.

It is an arithmetic number, because the mean of its divisors is an integer number (332640).

2^1989987 is an apocalyptic number.

1989987 is a deficient number, since it is larger than the sum of its proper divisors (671133).

1989987 is a wasteful number, since it uses less digits than its factorization.

1989987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1953.

The product of its digits is 326592, while the sum is 51.

The square root of 1989987 is about 1410.6689902312. The cubic root of 1989987 is about 125.7814932971.

The spelling of 1989987 in words is "one million, nine hundred eighty-nine thousand, nine hundred eighty-seven".