28781566523 has 4 divisors (see below), whose sum is σ = 28801458480. Its totient is φ = 28761674568.

The previous prime is 28781566501. The next prime is 28781566571. The reversal of 28781566523 is 32566518782.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28781566523 - 2¹⁶ = 28781500987 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28781566823) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9943808 + ... + 9946701.

It is an arithmetic number, because the mean of its divisors is an integer number (7200364620).

Almost surely, 2^28781566523 is an apocalyptic number.

28781566523 is a deficient number, since it is larger than the sum of its proper divisors (19891957).

28781566523 is a wasteful number, since it uses less digits than its factorization.

28781566523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19891956.

The product of its digits is 4838400, while the sum is 53.

The spelling of 28781566523 in words is "twenty-eight billion, seven hundred eighty-one million, five hundred sixty-six thousand, five hundred twenty-three".