688009401 has 6 divisors (see below), whose sum is σ = 993791370. Its totient is φ = 458672928.

The previous prime is 688009393. The next prime is 688009403. The reversal of 688009401 is 104900886.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 682463376 + 5546025 = 26124^2 + 2355^2 .

It is not a de Polignac number, because 688009401 - 2³ = 688009393 is a prime.

It is not an unprimeable number, because it can be changed into a prime (688009403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 38222736 + ... + 38222753.

It is an arithmetic number, because the mean of its divisors is an integer number (165631895).

Almost surely, 2^688009401 is an apocalyptic number.

It is an amenable number.

688009401 is a deficient number, since it is larger than the sum of its proper divisors (305781969).

688009401 is a wasteful number, since it uses less digits than its factorization.

688009401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76445495 (or 76445492 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 688009401 is about 26229.9333014783. The cubic root of 688009401 is about 882.8050134062.

The spelling of 688009401 in words is "six hundred eighty-eight million, nine thousand, four hundred one".