28380137778 has 128 divisors (see below), whose sum is σ = 67113446400. Its totient is φ = 8864640000.

The previous prime is 28380137777. The next prime is 28380137843. The reversal of 28380137778 is 87773108382.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (28380137771) 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 63 ways as a sum of consecutive naturals, for example, 49702233 + ... + 49702803.

It is an arithmetic number, because the mean of its divisors is an integer number (524323800).

Almost surely, 2^28380137778 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28380137778, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33556723200).

28380137778 is an abundant number, since it is smaller than the sum of its proper divisors (38733308622).

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

28380137778 is a wasteful number, since it uses less digits than its factorization.

28380137778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1045 (or 1039 counting only the distinct ones).

The product of its (nonzero) digits is 3161088, while the sum is 54.

The spelling of 28380137778 in words is "twenty-eight billion, three hundred eighty million, one hundred thirty-seven thousand, seven hundred seventy-eight".