16778664 has 128 divisors (see below), whose sum is σ = 54316800. Its totient is φ = 4758912.

The previous prime is 16778639. The next prime is 16778683. The reversal of 16778664 is 46687761.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 122404 + ... + 122540.

It is an arithmetic number, because the mean of its divisors is an integer number (424350).

Almost surely, 2^16778664 is an apocalyptic number.

16778664 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 16778664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27158400).

16778664 is an abundant number, since it is smaller than the sum of its proper divisors (37538136).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

16778664 is an equidigital number, since it uses as much as digits as its factorization.

16778664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171 (or 149 counting only the distinct ones).

The product of its digits is 338688, while the sum is 45.

The square root of 16778664 is about 4096.1767539988. The cubic root of 16778664 is about 256.0073646970.

The spelling of 16778664 in words is "sixteen million, seven hundred seventy-eight thousand, six hundred sixty-four".