28643696640 has 672 divisors, whose sum is σ = 110203853760. Its totient is φ = 6837239808.

The previous prime is 28643696621. The next prime is 28643696647. The reversal of 28643696640 is 4669634682.

28643696640 is a `hidden beast` number, since 2 + 86 + 436 + 96 + 6 + 40 = 666.

It is a super-2 number, since 2×28643696640² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28643696647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 206069691 + ... + 206069829.

It is an arithmetic number, because the mean of its divisors is an integer number (163993830).

Almost surely, 2^28643696640 is an apocalyptic number.

28643696640 is a gapful number since it is divisible by the number (20) 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 28643696640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (55101926880).

28643696640 is an abundant number, since it is smaller than the sum of its proper divisors (81560157120).

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

28643696640 is a wasteful number, since it uses less digits than its factorization.

28643696640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 232 (or 205 counting only the distinct ones).

The product of its (nonzero) digits is 8957952, while the sum is 54.

The spelling of 28643696640 in words is "twenty-eight billion, six hundred forty-three million, six hundred ninety-six thousand, six hundred forty".