28780821844 has 6 divisors (see below), whose sum is σ = 50366438234. Its totient is φ = 14390410920.

The previous prime is 28780821793. The next prime is 28780821851. The reversal of 28780821844 is 44812808782.

It can be written as a sum of positive squares in only one way, i.e., 26432256400 + 2348565444 = 162580^2 + 48462^2 .

It is a junction number, because it is equal to n+sod(n) for n = 28780821791 and 28780821800.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3597602727 + ... + 3597602734.

Almost surely, 2^28780821844 is an apocalyptic number.

It is an amenable number.

28780821844 is a deficient number, since it is larger than the sum of its proper divisors (21585616390).

28780821844 is a wasteful number, since it uses less digits than its factorization.

28780821844 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7195205465 (or 7195205463 counting only the distinct ones).

The product of its (nonzero) digits is 1835008, while the sum is 52.

The spelling of 28780821844 in words is "twenty-eight billion, seven hundred eighty million, eight hundred twenty-one thousand, eight hundred forty-four".