1640500000 has 168 divisors, whose sum is σ = 4296741876. Its totient is φ = 614400000.

The previous prime is 1640499989. The next prime is 1640500003. The reversal of 1640500000 is 50461.

It can be written as a sum of positive squares in 14 ways, for example, as 1423703824 + 216796176 = 37732^2 + 14724^2 .

It is a Harshad number since it is a multiple of its sum of digits (16).

It is not an unprimeable number, because it can be changed into a prime (1640500003) by changing a digit.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 8499904 + ... + 8500096.

Almost surely, 2^1640500000 is an apocalyptic number.

1640500000 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 1640500000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2148370938).

1640500000 is an abundant number, since it is smaller than the sum of its proper divisors (2656241876).

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

1640500000 is an frugal number, since it uses more digits than its factorization.

1640500000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 250 (or 217 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 1640500000 is about 40503.0863021573. The cubic root of 1640500000 is about 1179.3935407058.

Adding to 1640500000 its reverse (50461), we get a palindrome (1640550461).

The spelling of 1640500000 in words is "one billion, six hundred forty million, five hundred thousand".