1028601640 has 72 divisors (see below), whose sum is σ = 2549406510. Its totient is φ = 373225600.

The previous prime is 1028601611. The next prime is 1028601647. The reversal of 1028601640 is 461068201.

It can be written as a sum of positive squares in 3 ways, for example, as 654643396 + 373958244 = 25586^2 + 19338^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1028601599 and 1028601608.

It is not an unprimeable number, because it can be changed into a prime (1028601647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 2231010 + ... + 2231470.

Almost surely, 2^1028601640 is an apocalyptic number.

1028601640 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 1028601640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1274703255).

1028601640 is an abundant number, since it is smaller than the sum of its proper divisors (1520804870).

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

1028601640 is an equidigital number, since it uses as much as digits as its factorization.

1028601640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 955 (or 479 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 28.

The square root of 1028601640 is about 32071.8200294277. The cubic root of 1028601640 is about 1009.4444024589. Note that the first 4 decimals are identical.

Adding to 1028601640 its reverse (461068201), we get a palindrome (1489669841).

The spelling of 1028601640 in words is "one billion, twenty-eight million, six hundred one thousand, six hundred forty".