688643257 has 16 divisors (see below), whose sum is σ = 721768320. Its totient is φ = 656406400.

The previous prime is 688643243. The next prime is 688643303. The reversal of 688643257 is 752346886.

It is a cyclic number.

It is not a de Polignac number, because 688643257 - 2²³ = 680254649 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 688643257.

It is not an unprimeable number, because it can be changed into a prime (688640257) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 675294 + ... + 676312.

It is an arithmetic number, because the mean of its divisors is an integer number (45110520).

Almost surely, 2^688643257 is an apocalyptic number.

It is an amenable number.

688643257 is a deficient number, since it is larger than the sum of its proper divisors (33125063).

688643257 is a wasteful number, since it uses less digits than its factorization.

688643257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1424.

The product of its digits is 1935360, while the sum is 49.

The square root of 688643257 is about 26242.0132040208. The cubic root of 688643257 is about 883.0760365925.

It can be divided in two parts, 688643 and 257, that added together give a square (688900 = 830²).

The spelling of 688643257 in words is "six hundred eighty-eight million, six hundred forty-three thousand, two hundred fifty-seven".