1640380240 has 80 divisors (see below), whose sum is σ = 4016707200. Its totient is φ = 621789696.

The previous prime is 1640380223. The next prime is 1640380243. The reversal of 1640380240 is 420830461.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 1640380199 and 1640380208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640380243) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 196471 + ... + 204649.

It is an arithmetic number, because the mean of its divisors is an integer number (50208840).

Almost surely, 2^1640380240 is an apocalyptic number.

1640380240 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 1640380240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2008353600).

1640380240 is an abundant number, since it is smaller than the sum of its proper divisors (2376326960).

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

1640380240 is a wasteful number, since it uses less digits than its factorization.

1640380240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8324 (or 8318 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 28.

The square root of 1640380240 is about 40501.6078693180. The cubic root of 1640380240 is about 1179.3648405925.

The spelling of 1640380240 in words is "one billion, six hundred forty million, three hundred eighty thousand, two hundred forty".