1640380872 has 96 divisors (see below), whose sum is σ = 4564304640. Its totient is φ = 488361600.

The previous prime is 1640380867. The next prime is 1640380877. The reversal of 1640380872 is 2780830461.

It is an interprime number because it is at equal distance from previous prime (1640380867) and next prime (1640380877).

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a self number, because there is not a number n which added to its sum of digits gives 1640380872.

It is not an unprimeable number, because it can be changed into a prime (1640380877) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 297097 + ... + 302567.

It is an arithmetic number, because the mean of its divisors is an integer number (47544840).

Almost surely, 2^1640380872 is an apocalyptic number.

1640380872 is a gapful number since it is divisible by the number (12) 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 1640380872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2282152320).

1640380872 is an abundant number, since it is smaller than the sum of its proper divisors (2923923768).

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

1640380872 is a wasteful number, since it uses less digits than its factorization.

1640380872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5555 (or 5520 counting only the distinct ones).

The product of its (nonzero) digits is 64512, while the sum is 39.

The square root of 1640380872 is about 40501.6156714766. The cubic root of 1640380872 is about 1179.3649920530.

The spelling of 1640380872 in words is "one billion, six hundred forty million, three hundred eighty thousand, eight hundred seventy-two".