28256323897 has 4 divisors (see below), whose sum is σ = 28390240336. Its totient is φ = 28122407460.

The previous prime is 28256323891. The next prime is 28256323919. The reversal of 28256323897 is 79832365282.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 79832365282 = 2 ⋅39916182641.

It is a cyclic number.

It is not a de Polignac number, because 28256323897 - 2⁷ = 28256323769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28256323891) 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, 66957903 + ... + 66958324.

It is an arithmetic number, because the mean of its divisors is an integer number (7097560084).

Almost surely, 2^28256323897 is an apocalyptic number.

It is an amenable number.

28256323897 is a deficient number, since it is larger than the sum of its proper divisors (133916439).

28256323897 is a wasteful number, since it uses less digits than its factorization.

28256323897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133916438.

The product of its digits is 8709120, while the sum is 55.

The spelling of 28256323897 in words is "twenty-eight billion, two hundred fifty-six million, three hundred twenty-three thousand, eight hundred ninety-seven".