68400221 has 4 divisors (see below), whose sum is σ = 68795772. Its totient is φ = 68004672.

The previous prime is 68400169. The next prime is 68400223. The reversal of 68400221 is 12200486.

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 45225625 + 23174596 = 6725^2 + 4814^2 .

It is a cyclic number.

It is not a de Polignac number, because 68400221 - 2²⁶ = 1291357 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 (68400223) 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, 197516 + ... + 197861.

It is an arithmetic number, because the mean of its divisors is an integer number (17198943).

Almost surely, 2^68400221 is an apocalyptic number.

It is an amenable number.

68400221 is a deficient number, since it is larger than the sum of its proper divisors (395551).

68400221 is a wasteful number, since it uses less digits than its factorization.

68400221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 395550.

The product of its (nonzero) digits is 768, while the sum is 23.

The square root of 68400221 is about 8270.4426120976. The cubic root of 68400221 is about 408.9647110193.

The spelling of 68400221 in words is "sixty-eight million, four hundred thousand, two hundred twenty-one".