28081660565 has 64 divisors (see below), whose sum is σ = 40981248000. Its totient is φ = 18044570880.

The previous prime is 28081660547. The next prime is 28081660571. The reversal of 28081660565 is 56506618082.

It is a happy number.

It is not a de Polignac number, because 28081660565 - 2⁸ = 28081660309 is a prime.

It is a super-2 number, since 2×28081660565² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 42612206 + ... + 42612864.

It is an arithmetic number, because the mean of its divisors is an integer number (640332000).

Almost surely, 2^28081660565 is an apocalyptic number.

It is an amenable number.

28081660565 is a deficient number, since it is larger than the sum of its proper divisors (12899587435).

28081660565 is a wasteful number, since it uses less digits than its factorization.

28081660565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1290.

The product of its (nonzero) digits is 691200, while the sum is 47.

The spelling of 28081660565 in words is "twenty-eight billion, eighty-one million, six hundred sixty thousand, five hundred sixty-five".