28640291217 has 4 divisors (see below), whose sum is σ = 38187054960. Its totient is φ = 19093527476.

The previous prime is 28640291213. The next prime is 28640291227. The reversal of 28640291217 is 71219204682.

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.

It is a cyclic number.

It is not a de Polignac number, because 28640291217 - 2² = 28640291213 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28640291213) 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, 4773381867 + ... + 4773381872.

It is an arithmetic number, because the mean of its divisors is an integer number (9546763740).

Almost surely, 2^28640291217 is an apocalyptic number.

It is an amenable number.

28640291217 is a deficient number, since it is larger than the sum of its proper divisors (9546763743).

28640291217 is an equidigital number, since it uses as much as digits as its factorization.

28640291217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9546763742.

The product of its (nonzero) digits is 96768, while the sum is 42.

Adding to 28640291217 its reverse (71219204682), we get a palindrome (99859495899).

The spelling of 28640291217 in words is "twenty-eight billion, six hundred forty million, two hundred ninety-one thousand, two hundred seventeen".