28689631656 has 128 divisors (see below), whose sum is σ = 82731559680. Its totient is φ = 8121286656.

The previous prime is 28689631651. The next prime is 28689631657. The reversal of 28689631656 is 65613698682.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 28689631656.

It is not an unprimeable number, because it can be changed into a prime (28689631651) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8503986 + ... + 8507358.

It is an arithmetic number, because the mean of its divisors is an integer number (646340310).

Almost surely, 2^28689631656 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28689631656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41365779840).

28689631656 is an abundant number, since it is smaller than the sum of its proper divisors (54041928024).

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

28689631656 is a wasteful number, since it uses less digits than its factorization.

28689631656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3843 (or 3839 counting only the distinct ones).

The product of its digits is 22394880, while the sum is 60.

The spelling of 28689631656 in words is "twenty-eight billion, six hundred eighty-nine million, six hundred thirty-one thousand, six hundred fifty-six".