16405664 has 72 divisors (see below), whose sum is σ = 37537920. Its totient is φ = 7032960.

The previous prime is 16405657. The next prime is 16405667. The reversal of 16405664 is 46650461.

It is a super-2 number, since 2×16405664² = 538291622561792, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a self number, because there is not a number n which added to its sum of digits gives 16405664.

It is not an unprimeable number, because it can be changed into a prime (16405667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 73457 + ... + 73679.

It is an arithmetic number, because the mean of its divisors is an integer number (521360).

Almost surely, 2^16405664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 16405664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18768960).

16405664 is an abundant number, since it is smaller than the sum of its proper divisors (21132256).

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

16405664 is a wasteful number, since it uses less digits than its factorization.

16405664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 274 (or 255 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 32.

The square root of 16405664 is about 4050.3905984485. The cubic root of 16405664 is about 254.0960638559.

The spelling of 16405664 in words is "sixteen million, four hundred five thousand, six hundred sixty-four".