28756641780 has 36 divisors (see below), whose sum is σ = 87228480612. Its totient is φ = 7668437760.

The previous prime is 28756641763. The next prime is 28756641811. The reversal of 28756641780 is 8714665782.

28756641780 is a `hidden beast` number, since 2 + 8 + 7 + 566 + 4 + 1 + 78 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 17587533924 + 11169107856 = 132618^2 + 105684^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 79879381 + ... + 79879740.

Almost surely, 2^28756641780 is an apocalyptic number.

28756641780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28756641780 is an abundant number, since it is smaller than the sum of its proper divisors (58471838832).

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

28756641780 is a wasteful number, since it uses less digits than its factorization.

28756641780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159759136 (or 159759131 counting only the distinct ones).

The product of its (nonzero) digits is 4515840, while the sum is 54.

The spelling of 28756641780 in words is "twenty-eight billion, seven hundred fifty-six million, six hundred forty-one thousand, seven hundred eighty".