1640940640 has 192 divisors, whose sum is σ = 4320812160. Its totient is φ = 586055680.

The previous prime is 1640940629. The next prime is 1640940649. The reversal of 1640940640 is 460490461.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a junction number, because it is equal to n+sod(n) for n = 1640940596 and 1640940605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640940649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5600334 + ... + 5600626.

It is an arithmetic number, because the mean of its divisors is an integer number (22504230).

Almost surely, 2^1640940640 is an apocalyptic number.

1640940640 is a gapful number since it is divisible by the number (10) 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 1640940640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2160406080).

1640940640 is an abundant number, since it is smaller than the sum of its proper divisors (2679871520).

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

1640940640 is a wasteful number, since it uses less digits than its factorization.

1640940640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 425 (or 417 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 34.

The square root of 1640940640 is about 40508.5255224132. The cubic root of 1640940640 is about 1179.4991266953.

The spelling of 1640940640 in words is "one billion, six hundred forty million, nine hundred forty thousand, six hundred forty".