68640705 has 24 divisors (see below), whose sum is σ = 135974592. Its totient is φ = 31378464.

The previous prime is 68640703. The next prime is 68640721. The reversal of 68640705 is 50704686.

It is a happy number.

68640705 is a `hidden beast` number, since 6 + 8 + 640 + 7 + 0 + 5 = 666.

It is not a de Polignac number, because 68640705 - 2¹ = 68640703 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 68640705.

It is not an unprimeable number, because it can be changed into a prime (68640701) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 108639 + ... + 109268.

It is an arithmetic number, because the mean of its divisors is an integer number (5665608).

Almost surely, 2^68640705 is an apocalyptic number.

It is an amenable number.

68640705 is a deficient number, since it is larger than the sum of its proper divisors (67333887).

68640705 is a wasteful number, since it uses less digits than its factorization.

68640705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217925 (or 217922 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

The square root of 68640705 is about 8284.9686179249. The cubic root of 68640705 is about 409.4434347842.

The spelling of 68640705 in words is "sixty-eight million, six hundred forty thousand, seven hundred five".