817648667609 has 4 divisors (see below), whose sum is σ = 826835731380. Its totient is φ = 808461603840.

The previous prime is 817648667597. The next prime is 817648667623. The reversal of 817648667609 is 906766846718.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 906766846718 = 2 ⋅453383423359.

It can be written as a sum of positive squares in 2 ways, for example, as 468202168009 + 349446499600 = 684253^2 + 591140^2 .

It is a cyclic number.

It is not a de Polignac number, because 817648667609 - 2⁴ = 817648667593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (817648637609) 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, 4593531752 + ... + 4593531929.

It is an arithmetic number, because the mean of its divisors is an integer number (206708932845).

Almost surely, 2^817648667609 is an apocalyptic number.

817648667609 is a gapful number since it is divisible by the number (89) formed by its first and last digit.

It is an amenable number.

817648667609 is a deficient number, since it is larger than the sum of its proper divisors (9187063771).

817648667609 is an equidigital number, since it uses as much as digits as its factorization.

817648667609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9187063770.

The product of its (nonzero) digits is 146313216, while the sum is 68.

The spelling of 817648667609 in words is "eight hundred seventeen billion, six hundred forty-eight million, six hundred sixty-seven thousand, six hundred nine".