1688633645018 has 4 divisors (see below), whose sum is σ = 2532950467530. Its totient is φ = 844316822508.

The previous prime is 1688633644979. The next prime is 1688633645021. The reversal of 1688633645018 is 8105463368861.

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., 1579639244569 + 108994400449 = 1256837^2 + 330143^2 .

It is a super-3 number, since 3×1688633645018³ (a number of 38 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 422158411253 + ... + 422158411256.

Almost surely, 2^{1688633645018} is an apocalyptic number.

1688633645018 is a deficient number, since it is larger than the sum of its proper divisors (844316822512).

1688633645018 is an equidigital number, since it uses as much as digits as its factorization.

1688633645018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 844316822511.

The product of its (nonzero) digits is 19906560, while the sum is 59.

The spelling of 1688633645018 in words is "one trillion, six hundred eighty-eight billion, six hundred thirty-three million, six hundred forty-five thousand, eighteen".