688618103906 has 4 divisors (see below), whose sum is σ = 1032927155862. Its totient is φ = 344309051952.

The previous prime is 688618103867. The next prime is 688618103909. The reversal of 688618103906 is 609301816886.

It is a happy number.

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., 633789539881 + 54828564025 = 796109^2 + 234155^2 .

It is a super-2 number, since 2×688618103906² (a number of 24 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (688618103909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 172154525975 + ... + 172154525978.

Almost surely, 2^688618103906 is an apocalyptic number.

688618103906 is a deficient number, since it is larger than the sum of its proper divisors (344309051956).

688618103906 is a wasteful number, since it uses less digits than its factorization.

688618103906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 344309051955.

The product of its (nonzero) digits is 2985984, while the sum is 56.

The spelling of 688618103906 in words is "six hundred eighty-eight billion, six hundred eighteen million, one hundred three thousand, nine hundred six".