16187989 has 4 divisors (see below), whose sum is σ = 16582860. Its totient is φ = 15793120.

The previous prime is 16187987. The next prime is 16187993. The reversal of 16187989 is 98978161.

16187989 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in 2 ways, for example, as 4695889 + 11492100 = 2167^2 + 3390^2 .

It is a cyclic number.

It is not a de Polignac number, because 16187989 - 2¹ = 16187987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16187987) 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, 197374 + ... + 197455.

It is an arithmetic number, because the mean of its divisors is an integer number (4145715).

Almost surely, 2^16187989 is an apocalyptic number.

It is an amenable number.

16187989 is a deficient number, since it is larger than the sum of its proper divisors (394871).

16187989 is an equidigital number, since it uses as much as digits as its factorization.

16187989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 394870.

The product of its digits is 217728, while the sum is 49.

The square root of 16187989 is about 4023.4300043619. The cubic root of 16187989 is about 252.9672503657.

The spelling of 16187989 in words is "sixteen million, one hundred eighty-seven thousand, nine hundred eighty-nine".