28215255291 has 4 divisors (see below), whose sum is σ = 37620340392. Its totient is φ = 18810170192.

The previous prime is 28215255287. The next prime is 28215255293. The reversal of 28215255291 is 19255251282.

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 28215255291 - 2² = 28215255287 is a prime.

It is a super-2 number, since 2×28215255291² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28215255293) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4702542546 + ... + 4702542551.

It is an arithmetic number, because the mean of its divisors is an integer number (9405085098).

Almost surely, 2^28215255291 is an apocalyptic number.

28215255291 is a deficient number, since it is larger than the sum of its proper divisors (9405085101).

28215255291 is an equidigital number, since it uses as much as digits as its factorization.

28215255291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9405085100.

The product of its digits is 144000, while the sum is 42.

The spelling of 28215255291 in words is "twenty-eight billion, two hundred fifteen million, two hundred fifty-five thousand, two hundred ninety-one".