68640044 has 18 divisors (see below), whose sum is σ = 131145084. Its totient is φ = 31175040.

The previous prime is 68640037. The next prime is 68640049. The reversal of 68640044 is 44004686.

It is a super-2 number, since 2×68640044² = 9422911280643872, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (68640049) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 54332 + ... + 55580.

It is an arithmetic number, because the mean of its divisors is an integer number (7285838).

Almost surely, 2^68640044 is an apocalyptic number.

It is an amenable number.

68640044 is a deficient number, since it is larger than the sum of its proper divisors (62505040).

68640044 is a wasteful number, since it uses less digits than its factorization.

68640044 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2513 (or 1262 counting only the distinct ones).

The product of its (nonzero) digits is 18432, while the sum is 32.

The square root of 68640044 is about 8284.9287263078. The cubic root of 68640044 is about 409.4421204864.

The spelling of 68640044 in words is "sixty-eight million, six hundred forty thousand, forty-four".