68218681 has 4 divisors (see below), whose sum is σ = 68414500. Its totient is φ = 68022864.

The previous prime is 68218649. The next prime is 68218687. The reversal of 68218681 is 18681286.

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

It can be written as a sum of positive squares in 2 ways, for example, as 21706281 + 46512400 = 4659^2 + 6820^2 .

It is a cyclic number.

It is not a de Polignac number, because 68218681 - 2⁵ = 68218649 is a prime.

It is a super-2 number, since 2×68218681² = 9307576874759522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68218687) 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, 97386 + ... + 98083.

It is an arithmetic number, because the mean of its divisors is an integer number (17103625).

Almost surely, 2^68218681 is an apocalyptic number.

It is an amenable number.

68218681 is a deficient number, since it is larger than the sum of its proper divisors (195819).

68218681 is a wasteful number, since it uses less digits than its factorization.

68218681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195818.

The product of its digits is 36864, while the sum is 40.

The square root of 68218681 is about 8259.4600913135. The cubic root of 68218681 is about 408.6025814219.

The spelling of 68218681 in words is "sixty-eight million, two hundred eighteen thousand, six hundred eighty-one".