1640385044 has 12 divisors (see below), whose sum is σ = 2909998644. Its totient is φ = 808956864.

The previous prime is 1640384987. The next prime is 1640385049. The reversal of 1640385044 is 4405830461.

It can be written as a sum of positive squares in 2 ways, for example, as 670810000 + 969575044 = 25900^2 + 31138^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1640384995 and 1640385013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640385049) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2808587 + ... + 2809170.

It is an arithmetic number, because the mean of its divisors is an integer number (242499887).

Almost surely, 2^1640385044 is an apocalyptic number.

It is an amenable number.

1640385044 is a deficient number, since it is larger than the sum of its proper divisors (1269613600).

1640385044 is a wasteful number, since it uses less digits than its factorization.

1640385044 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5617834 (or 5617832 counting only the distinct ones).

The product of its (nonzero) digits is 46080, while the sum is 35.

The square root of 1640385044 is about 40501.6671755620. The cubic root of 1640385044 is about 1179.3659918831.

The spelling of 1640385044 in words is "one billion, six hundred forty million, three hundred eighty-five thousand, forty-four".