16623989 has 8 divisors (see below), whose sum is σ = 17663160. Its totient is φ = 15615936.

The previous prime is 16623961. The next prime is 16624001. The reversal of 16623989 is 98932661.

It can be written as a sum of positive squares in 4 ways, for example, as 1932100 + 14691889 = 1390^2 + 3833^2 .

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 16623989 - 2¹⁶ = 16558453 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a nialpdrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16623949) 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, 6674 + ... + 8819.

It is an arithmetic number, because the mean of its divisors is an integer number (2207895).

Almost surely, 2^16623989 is an apocalyptic number.

It is an amenable number.

16623989 is a deficient number, since it is larger than the sum of its proper divisors (1039171).

16623989 is a wasteful number, since it uses less digits than its factorization.

16623989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15559.

The product of its digits is 139968, while the sum is 44.

The square root of 16623989 is about 4077.2526289157. The cubic root of 16623989 is about 255.2182624434.

The spelling of 16623989 in words is "sixteen million, six hundred twenty-three thousand, nine hundred eighty-nine".