68640863 has 4 divisors (see below), whose sum is σ = 72253560. Its totient is φ = 65028168.

The previous prime is 68640839. The next prime is 68640881. The reversal of 68640863 is 36804686.

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

It is a cyclic number.

It is not a de Polignac number, because 68640863 - 2¹⁶ = 68575327 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 68640863.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (68640823) 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 3 ways as a sum of consecutive naturals, for example, 1806320 + ... + 1806357.

It is an arithmetic number, because the mean of its divisors is an integer number (18063390).

Almost surely, 2^68640863 is an apocalyptic number.

68640863 is a deficient number, since it is larger than the sum of its proper divisors (3612697).

68640863 is a wasteful number, since it uses less digits than its factorization.

68640863 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3612696.

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

The square root of 68640863 is about 8284.9781532603. The cubic root of 68640863 is about 409.4437489418.

The spelling of 68640863 in words is "sixty-eight million, six hundred forty thousand, eight hundred sixty-three".