68815221 has 4 divisors (see below), whose sum is σ = 91753632. Its totient is φ = 45876812.

The previous prime is 68815213. The next prime is 68815247. The reversal of 68815221 is 12251886.

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 not a de Polignac number, because 68815221 - 2³ = 68815213 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (68815211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11469201 + ... + 11469206.

It is an arithmetic number, because the mean of its divisors is an integer number (22938408).

Almost surely, 2^68815221 is an apocalyptic number.

It is an amenable number.

68815221 is a deficient number, since it is larger than the sum of its proper divisors (22938411).

68815221 is a wasteful number, since it uses less digits than its factorization.

68815221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22938410.

The product of its digits is 7680, while the sum is 33.

The square root of 68815221 is about 8295.4940178388. The cubic root of 68815221 is about 409.7901384846.

The spelling of 68815221 in words is "sixty-eight million, eight hundred fifteen thousand, two hundred twenty-one".