40001664 has 64 divisors (see below), whose sum is σ = 107785440. Its totient is φ = 13142016.

The previous prime is 40001657. The next prime is 40001711. The reversal of 40001664 is 46610004.

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 40001664.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27319 + ... + 28745.

Almost surely, 2^40001664 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 40001664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (53892720).

40001664 is an abundant number, since it is smaller than the sum of its proper divisors (67783776).

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

40001664 is a wasteful number, since it uses less digits than its factorization.

40001664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1517 (or 1505 counting only the distinct ones).

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

The square root of 40001664 is about 6324.6868697193. The cubic root of 40001664 is about 341.9999316029. Note that the first 4 decimals are identical.

Adding to 40001664 its reverse (46610004), we get a palindrome (86611668).

The spelling of 40001664 in words is "forty million, one thousand, six hundred sixty-four".