28639688780 has 48 divisors (see below), whose sum is σ = 62832369600. Its totient is φ = 10944857088.

The previous prime is 28639688767. The next prime is 28639688789. The reversal of 28639688780 is 8788693682.

It is not an unprimeable number, because it can be changed into a prime (28639688789) 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, 357896 + ... + 430544.

It is an arithmetic number, because the mean of its divisors is an integer number (1309007700).

Almost surely, 2^28639688780 is an apocalyptic number.

28639688780 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 28639688780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31416184800).

28639688780 is an abundant number, since it is smaller than the sum of its proper divisors (34192680820).

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

28639688780 is a wasteful number, since it uses less digits than its factorization.

28639688780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73538 (or 73536 counting only the distinct ones).

The product of its (nonzero) digits is 55738368, while the sum is 65.

The spelling of 28639688780 in words is "twenty-eight billion, six hundred thirty-nine million, six hundred eighty-eight thousand, seven hundred eighty".