68640638 has 12 divisors (see below), whose sum is σ = 113172360. Its totient is φ = 31200180.

The previous prime is 68640631. The next prime is 68640647. The reversal of 68640638 is 83604686.

It is a junction number, because it is equal to n+sod(n) for n = 68640595 and 68640604.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (68640631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 141578 + ... + 142061.

It is an arithmetic number, because the mean of its divisors is an integer number (9431030).

Almost surely, 2^68640638 is an apocalyptic number.

68640638 is a deficient number, since it is larger than the sum of its proper divisors (44531722).

68640638 is a wasteful number, since it uses less digits than its factorization.

68640638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 283663 (or 283652 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 41.

The square root of 68640638 is about 8284.9645744565. The cubic root of 68640638 is about 409.4433015653.

The spelling of 68640638 in words is "sixty-eight million, six hundred forty thousand, six hundred thirty-eight".