28780111900 has 18 divisors (see below), whose sum is σ = 62452843040. Its totient is φ = 11512044720.

The previous prime is 28780111897. The next prime is 28780111949. The reversal of 28780111900 is 911108782.

It is a super-2 number, since 2×28780111900² (a number of 22 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 28780111900.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 143900460 + ... + 143900659.

Almost surely, 2^28780111900 is an apocalyptic number.

28780111900 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28780111900 is an abundant number, since it is smaller than the sum of its proper divisors (33672731140).

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

28780111900 is a wasteful number, since it uses less digits than its factorization.

28780111900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 287801133 (or 287801126 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 37.

The spelling of 28780111900 in words is "twenty-eight billion, seven hundred eighty million, one hundred eleven thousand, nine hundred".