16990861 has 4 divisors (see below), whose sum is σ = 17027712. Its totient is φ = 16954012.

The previous prime is 16990843. The next prime is 16990873. The reversal of 16990861 is 16809961.

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, and also an emirpimes, since its reverse is a distinct semiprime: 16809961 = 7 ⋅2401423.

It is a cyclic number.

It is not a de Polignac number, because 16990861 - 2¹⁵ = 16958093 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16990801) 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, 17725 + ... + 18658.

It is an arithmetic number, because the mean of its divisors is an integer number (4256928).

Almost surely, 2^16990861 is an apocalyptic number.

It is an amenable number.

16990861 is a deficient number, since it is larger than the sum of its proper divisors (36851).

16990861 is an equidigital number, since it uses as much as digits as its factorization.

16990861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36850.

The product of its (nonzero) digits is 23328, while the sum is 40.

The square root of 16990861 is about 4121.9972100912. The cubic root of 16990861 is about 257.0820744489.

The spelling of 16990861 in words is "sixteen million, nine hundred ninety thousand, eight hundred sixty-one".