28505282781 has 16 divisors (see below), whose sum is σ = 39240734720. Its totient is φ = 18386915760.

The previous prime is 28505282777. The next prime is 28505282789. The reversal of 28505282781 is 18728250582.

It is not a de Polignac number, because 28505282781 - 2² = 28505282777 is a prime.

It is a super-2 number, since 2×28505282781² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28505282781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28505282789) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 499206 + ... + 553368.

It is an arithmetic number, because the mean of its divisors is an integer number (2452545920).

Almost surely, 2^28505282781 is an apocalyptic number.

It is an amenable number.

28505282781 is a deficient number, since it is larger than the sum of its proper divisors (10735451939).

28505282781 is a wasteful number, since it uses less digits than its factorization.

28505282781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59856.

The product of its (nonzero) digits is 716800, while the sum is 48.

The spelling of 28505282781 in words is "twenty-eight billion, five hundred five million, two hundred eighty-two thousand, seven hundred eighty-one".