16861009 has 8 divisors (see below), whose sum is σ = 18653760. Its totient is φ = 15111600.

The previous prime is 16861003. The next prime is 16861021. The reversal of 16861009 is 90016861.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 16861009 - 2²¹ = 14763857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16861003) 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, 10014 + ... + 11575.

It is an arithmetic number, because the mean of its divisors is an integer number (2331720).

Almost surely, 2^16861009 is an apocalyptic number.

It is an amenable number.

16861009 is a deficient number, since it is larger than the sum of its proper divisors (1792751).

16861009 is a wasteful number, since it uses less digits than its factorization.

16861009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21671.

The product of its (nonzero) digits is 2592, while the sum is 31.

The square root of 16861009 is about 4106.2158978797. The cubic root of 16861009 is about 256.4254856656.

The spelling of 16861009 in words is "sixteen million, eight hundred sixty-one thousand, nine".