16781689 has 4 divisors (see below), whose sum is σ = 16793424. Its totient is φ = 16769956.

The previous prime is 16781671. The next prime is 16781701. The reversal of 16781689 is 98618761.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 16781689 - 2¹⁹ = 16257401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16781629) 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, 3367 + ... + 6700.

It is an arithmetic number, because the mean of its divisors is an integer number (4198356).

Almost surely, 2^16781689 is an apocalyptic number.

It is an amenable number.

16781689 is a deficient number, since it is larger than the sum of its proper divisors (11735).

16781689 is a wasteful number, since it uses less digits than its factorization.

16781689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11734.

The product of its digits is 145152, while the sum is 46.

The square root of 16781689 is about 4096.5459841188. The cubic root of 16781689 is about 256.0227488329.

The spelling of 16781689 in words is "sixteen million, seven hundred eighty-one thousand, six hundred eighty-nine".