688421501 has 2 divisors, whose sum is σ = 688421502. Its totient is φ = 688421500.

The previous prime is 688421473. The next prime is 688421507. The reversal of 688421501 is 105124886.

688421501 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 355322500 + 333099001 = 18850^2 + 18251^2 .

It is a cyclic number.

It is not a de Polignac number, because 688421501 - 2¹⁰ = 688420477 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (688421507) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344210750 + 344210751.

It is an arithmetic number, because the mean of its divisors is an integer number (344210751).

Almost surely, 2^688421501 is an apocalyptic number.

It is an amenable number.

688421501 is a deficient number, since it is larger than the sum of its proper divisors (1).

688421501 is an equidigital number, since it uses as much as digits as its factorization.

688421501 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15360, while the sum is 35.

The square root of 688421501 is about 26237.7876544498. The cubic root of 688421501 is about 882.9812374196.

The spelling of 688421501 in words is "six hundred eighty-eight million, four hundred twenty-one thousand, five hundred one".