688421213 has 2 divisors, whose sum is σ = 688421214. Its totient is φ = 688421212.

The previous prime is 688421191. The next prime is 688421249. The reversal of 688421213 is 312124886.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 407959204 + 280462009 = 20198^2 + 16747^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-688421213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (688423213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344210606 + 344210607.

It is an arithmetic number, because the mean of its divisors is an integer number (344210607).

Almost surely, 2^688421213 is an apocalyptic number.

It is an amenable number.

688421213 is a deficient number, since it is larger than the sum of its proper divisors (1).

688421213 is an equidigital number, since it uses as much as digits as its factorization.

688421213 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18432, while the sum is 35.

The square root of 688421213 is about 26237.7821661817. The cubic root of 688421213 is about 882.9811142884.

The spelling of 688421213 in words is "six hundred eighty-eight million, four hundred twenty-one thousand, two hundred thirteen".