16720609 has 4 divisors (see below), whose sum is σ = 17447616. Its totient is φ = 15993604.

The previous prime is 16720607. The next prime is 16720619. The reversal of 16720609 is 90602761.

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: 90602761 = 307 ⋅295123.

It is a cyclic number.

It is not a de Polignac number, because 16720609 - 2¹ = 16720607 is a prime.

It is not an unprimeable number, because it can be changed into a prime (16720601) 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, 363469 + ... + 363514.

It is an arithmetic number, because the mean of its divisors is an integer number (4361904).

Almost surely, 2^16720609 is an apocalyptic number.

It is an amenable number.

16720609 is a deficient number, since it is larger than the sum of its proper divisors (727007).

16720609 is an equidigital number, since it uses as much as digits as its factorization.

16720609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 727006.

The product of its (nonzero) digits is 4536, while the sum is 31.

The square root of 16720609 is about 4089.0841272833. The cubic root of 16720609 is about 255.7117574851.

The spelling of 16720609 in words is "sixteen million, seven hundred twenty thousand, six hundred nine".