16720843 has 4 divisors (see below), whose sum is σ = 17704440. Its totient is φ = 15737248.

The previous prime is 16720841. The next prime is 16720859. The reversal of 16720843 is 34802761.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 34802761 = 7 ⋅4971823.

It is a cyclic number.

It is not a de Polignac number, because 16720843 - 2¹ = 16720841 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16720841) 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, 491773 + ... + 491806.

It is an arithmetic number, because the mean of its divisors is an integer number (4426110).

Almost surely, 2^16720843 is an apocalyptic number.

16720843 is a deficient number, since it is larger than the sum of its proper divisors (983597).

16720843 is an equidigital number, since it uses as much as digits as its factorization.

16720843 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 983596.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 16720843 is about 4089.1127399474. The cubic root of 16720843 is about 255.7129503498.

The spelling of 16720843 in words is "sixteen million, seven hundred twenty thousand, eight hundred forty-three".