21016689 has 8 divisors (see below), whose sum is σ = 28132320. Its totient is φ = 13956096.

The previous prime is 21016669. The next prime is 21016691. The reversal of 21016689 is 98661012.

21016689 is an esthetic number in base 7, because in such base its adjacent digits differ by 1.

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

It is not a de Polignac number, because 21016689 - 2⁵ = 21016657 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21016609) 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, 12859 + ... + 14400.

It is an arithmetic number, because the mean of its divisors is an integer number (3516540).

Almost surely, 2^21016689 is an apocalyptic number.

It is an amenable number.

21016689 is a deficient number, since it is larger than the sum of its proper divisors (7115631).

21016689 is a wasteful number, since it uses less digits than its factorization.

21016689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27519.

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 21016689 is about 4584.3962525070. The cubic root of 21016689 is about 275.9654835012.

The spelling of 21016689 in words is "twenty-one million, sixteen thousand, six hundred eighty-nine".