688249644 has 12 divisors (see below), whose sum is σ = 1605915864. Its totient is φ = 229416544.

The previous prime is 688249643. The next prime is 688249651. The reversal of 688249644 is 446942886.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-2 number, since 2×688249644² = 947375144932253472, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (688249643) 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, 28677057 + ... + 28677080.

It is an arithmetic number, because the mean of its divisors is an integer number (133826322).

Almost surely, 2^688249644 is an apocalyptic number.

It is an amenable number.

688249644 is an abundant number, since it is smaller than the sum of its proper divisors (917666220).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

688249644 is a wasteful number, since it uses less digits than its factorization.

688249644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57354144 (or 57354142 counting only the distinct ones).

The product of its digits is 2654208, while the sum is 51.

The square root of 688249644 is about 26234.5124597352. The cubic root of 688249644 is about 882.9077557250.

The spelling of 688249644 in words is "six hundred eighty-eight million, two hundred forty-nine thousand, six hundred forty-four".