16656289 has 4 divisors (see below), whose sum is σ = 17937556. Its totient is φ = 15375024.

The previous prime is 16656239. The next prime is 16656307. The reversal of 16656289 is 98265661.

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 9000000 + 7656289 = 3000^2 + 2767^2 .

It is a cyclic number.

It is not a de Polignac number, because 16656289 - 2⁹ = 16655777 is a prime.

It is not an unprimeable number, because it can be changed into a prime (16656239) 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, 640614 + ... + 640639.

It is an arithmetic number, because the mean of its divisors is an integer number (4484389).

Almost surely, 2^16656289 is an apocalyptic number.

It is an amenable number.

16656289 is a deficient number, since it is larger than the sum of its proper divisors (1281267).

16656289 is a wasteful number, since it uses less digits than its factorization.

16656289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1281266.

The product of its digits is 155520, while the sum is 43.

The square root of 16656289 is about 4081.2117073242. The cubic root of 16656289 is about 255.3834497646.

The spelling of 16656289 in words is "sixteen million, six hundred fifty-six thousand, two hundred eighty-nine".