4001664 has 64 divisors (see below), whose sum is σ = 11273040. Its totient is φ = 1253376.

The previous prime is 4001639. The next prime is 4001689. The reversal of 4001664 is 4661004.

It is an interprime number because it is at equal distance from previous prime (4001639) and next prime (4001689).

It is a tau number, because it is divible by the number of its divisors (64).

It is a self number, because there is not a number n which added to its sum of digits gives 4001664.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6222 + ... + 6834.

Almost surely, 2^4001664 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 4001664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5636520).

4001664 is an abundant number, since it is smaller than the sum of its proper divisors (7271376).

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

4001664 is a wasteful number, since it uses less digits than its factorization.

4001664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 647 (or 635 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 4001664 is about 2000.4159567450. The cubic root of 4001664 is about 158.7621141065.

Adding to 4001664 its reverse (4661004), we get a palindrome (8662668).

The spelling of 4001664 in words is "four million, one thousand, six hundred sixty-four".