16623409 has 24 divisors (see below), whose sum is σ = 19848960. Its totient is φ = 13776000.

The previous prime is 16623407. The next prime is 16623419. The reversal of 16623409 is 90432661.

It is not a de Polignac number, because 16623409 - 2¹ = 16623407 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a Duffinian number.

It is a nialpdrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (16623401) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 405429 + ... + 405469.

It is an arithmetic number, because the mean of its divisors is an integer number (827040).

Almost surely, 2^16623409 is an apocalyptic number.

It is an amenable number.

16623409 is a deficient number, since it is larger than the sum of its proper divisors (3225551).

16623409 is a wasteful number, since it uses less digits than its factorization.

16623409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153 (or 112 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 16623409 is about 4077.1815019692. The cubic root of 16623409 is about 255.2152942767.

The spelling of 16623409 in words is "sixteen million, six hundred twenty-three thousand, four hundred nine".