16656638 has 4 divisors (see below), whose sum is σ = 24984960. Its totient is φ = 8328318.

The previous prime is 16656631. The next prime is 16656649. The reversal of 16656638 is 83665661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 83665661 = 79 ⋅1059059.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 16656595 and 16656604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16656631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4164158 + ... + 4164161.

It is an arithmetic number, because the mean of its divisors is an integer number (6246240).

Almost surely, 2^16656638 is an apocalyptic number.

16656638 is a deficient number, since it is larger than the sum of its proper divisors (8328322).

16656638 is an equidigital number, since it uses as much as digits as its factorization.

16656638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8328321.

The product of its digits is 155520, while the sum is 41.

The square root of 16656638 is about 4081.2544640098. The cubic root of 16656638 is about 255.3852334392.

The spelling of 16656638 in words is "sixteen million, six hundred fifty-six thousand, six hundred thirty-eight".