1640409216 has 64 divisors (see below), whose sum is σ = 4391777280. Its totient is φ = 542481408.

The previous prime is 1640409119. The next prime is 1640409223. The reversal of 1640409216 is 6129040461.

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

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 31950 + ... + 65586.

It is an arithmetic number, because the mean of its divisors is an integer number (68621520).

Almost surely, 2^1640409216 is an apocalyptic number.

1640409216 is a gapful number since it is divisible by the number (16) 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 1640409216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2195888640).

1640409216 is an abundant number, since it is smaller than the sum of its proper divisors (2751368064).

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

1640409216 is a wasteful number, since it uses less digits than its factorization.

1640409216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33781 (or 33769 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 33.

The square root of 1640409216 is about 40501.9655819319. The cubic root of 1640409216 is about 1179.3717847293.

Adding to 1640409216 its reverse (6129040461), we get a palindrome (7769449677).

The spelling of 1640409216 in words is "one billion, six hundred forty million, four hundred nine thousand, two hundred sixteen".