16003664 has 30 divisors (see below), whose sum is σ = 32947854. Its totient is φ = 7528960.

The previous prime is 16003661. The next prime is 16003667. The reversal of 16003664 is 46630061.

It is an interprime number because it is at equal distance from previous prime (16003661) and next prime (16003667).

It can be written as a sum of positive squares in 3 ways, for example, as 4032064 + 11971600 = 2008^2 + 3460^2 .

It is a super-2 number, since 2×16003664² = 512234522849792, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16003661) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2894 + ... + 6354.

Almost surely, 2^16003664 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 16003664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (16473927).

16003664 is an abundant number, since it is smaller than the sum of its proper divisors (16944190).

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

16003664 is a wasteful number, since it uses less digits than its factorization.

16003664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3503 (or 3480 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 26.

The square root of 16003664 is about 4000.4579737825. The cubic root of 16003664 is about 252.0034433056.

The spelling of 16003664 in words is "sixteen million, three thousand, six hundred sixty-four".