28815118640 has 80 divisors (see below), whose sum is σ = 83526439680. Its totient is φ = 8981333760.

The previous prime is 28815118639. The next prime is 28815118721. The reversal of 28815118640 is 4681151882.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×28815118640² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a junction number, because it is equal to n+sod(n) for n = 28815118591 and 28815118600.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2332730 + ... + 2345049.

It is an arithmetic number, because the mean of its divisors is an integer number (1044080496).

Almost surely, 2^28815118640 is an apocalyptic number.

28815118640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28815118640 is an abundant number, since it is smaller than the sum of its proper divisors (54711321040).

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

28815118640 is a wasteful number, since it uses less digits than its factorization.

28815118640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4677810 (or 4677804 counting only the distinct ones).

The product of its (nonzero) digits is 122880, while the sum is 44.

The spelling of 28815118640 in words is "twenty-eight billion, eight hundred fifteen million, one hundred eighteen thousand, six hundred forty".