688564217 has 4 divisors (see below), whose sum is σ = 751160976. Its totient is φ = 625967460.

The previous prime is 688564193. The next prime is 688564223. The reversal of 688564217 is 712465886.

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 688564217 - 2¹⁴ = 688547833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (688564267) 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, 31298363 + ... + 31298384.

It is an arithmetic number, because the mean of its divisors is an integer number (187790244).

Almost surely, 2^688564217 is an apocalyptic number.

It is an amenable number.

688564217 is a deficient number, since it is larger than the sum of its proper divisors (62596759).

688564217 is a wasteful number, since it uses less digits than its factorization.

688564217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62596758.

The product of its digits is 645120, while the sum is 47.

The square root of 688564217 is about 26240.5071787875. The cubic root of 688564217 is about 883.0422498677.

The spelling of 688564217 in words is "six hundred eighty-eight million, five hundred sixty-four thousand, two hundred seventeen".