68640307 has 4 divisors (see below), whose sum is σ = 69320016. Its totient is φ = 67960600.

The previous prime is 68640289. The next prime is 68640317. The reversal of 68640307 is 70304686.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-68640307 is a prime.

It is a super-2 number, since 2×68640307² = 9422983490108498, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68640317) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 339703 + ... + 339904.

It is an arithmetic number, because the mean of its divisors is an integer number (17330004).

Almost surely, 2^68640307 is an apocalyptic number.

68640307 is a deficient number, since it is larger than the sum of its proper divisors (679709).

68640307 is a wasteful number, since it uses less digits than its factorization.

68640307 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 679708.

The product of its (nonzero) digits is 24192, while the sum is 34.

The square root of 68640307 is about 8284.9445984871. The cubic root of 68640307 is about 409.4426434228.

The spelling of 68640307 in words is "sixty-eight million, six hundred forty thousand, three hundred seven".