688398554 has 4 divisors (see below), whose sum is σ = 1032597834. Its totient is φ = 344199276.

The previous prime is 688398553. The next prime is 688398563. The reversal of 688398554 is 455893886.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 579509329 + 108889225 = 24073^2 + 10435^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 688398554.

It is not an unprimeable number, because it can be changed into a prime (688398553) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 172099637 + ... + 172099640.

Almost surely, 2^688398554 is an apocalyptic number.

688398554 is a deficient number, since it is larger than the sum of its proper divisors (344199280).

688398554 is a wasteful number, since it uses less digits than its factorization.

688398554 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 344199279.

The product of its digits is 8294400, while the sum is 56.

The square root of 688398554 is about 26237.3503616505. The cubic root of 688398554 is about 882.9714265719.

The spelling of 688398554 in words is "six hundred eighty-eight million, three hundred ninety-eight thousand, five hundred fifty-four".