68218661 has 4 divisors (see below), whose sum is σ = 77964192. Its totient is φ = 58473132.

The previous prime is 68218649. The next prime is 68218687. The reversal of 68218661 is 16681286.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-68218661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (68218061) 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, 4872755 + ... + 4872768.

It is an arithmetic number, because the mean of its divisors is an integer number (19491048).

Almost surely, 2^68218661 is an apocalyptic number.

It is an amenable number.

68218661 is a deficient number, since it is larger than the sum of its proper divisors (9745531).

68218661 is an equidigital number, since it uses as much as digits as its factorization.

68218661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9745530.

The product of its digits is 27648, while the sum is 38.

The square root of 68218661 is about 8259.4588805805. The cubic root of 68218661 is about 408.6025414912.

The spelling of 68218661 in words is "sixty-eight million, two hundred eighteen thousand, six hundred sixty-one".