688213 has 4 divisors (see below), whose sum is σ = 693760. Its totient is φ = 682668.

The previous prime is 688201. The next prime is 688217. The reversal of 688213 is 312886.

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 a de Polignac number, because none of the positive numbers 2^k-688213 is a prime.

It is a Duffinian number.

It is a zygodrome in base 4.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2583 + ... + 2836.

It is an arithmetic number, because the mean of its divisors is an integer number (173440).

It is a Poulet number, since it divides 2⁶⁸⁸²¹²-1.

2⁶⁸⁸²¹³ is an apocalyptic number.

It is an amenable number.

688213 is a deficient number, since it is larger than the sum of its proper divisors (5547).

688213 is a wasteful number, since it uses less digits than its factorization.

688213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5546.

The product of its digits is 2304, while the sum is 28.

The square root of 688213 is about 829.5860413483. The cubic root of 688213 is about 88.2892086098.

It can be divided in two parts, 68 and 8213, that added together give a square (8281 = 91²).

The spelling of 688213 in words is "six hundred eighty-eight thousand, two hundred thirteen".