68228721 has 24 divisors (see below), whose sum is σ = 109343520. Its totient is φ = 40646400.

The previous prime is 68228707. The next prime is 68228731. The reversal of 68228721 is 12782286.

It is a happy number.

68228721 is a nontrivial binomial coefficient, being equal to C(11682, 2).

It is not a de Polignac number, because 68228721 - 2¹⁰ = 68227697 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (68228731) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1 + ... + 11681.

It is an arithmetic number, because the mean of its divisors is an integer number (4555980).

Almost surely, 2^68228721 is an apocalyptic number.

68228721 is the 11681-st triangular number and also the 5841-st hexagonal number.

It is an amenable number.

68228721 is a deficient number, since it is larger than the sum of its proper divisors (41114799).

68228721 is a wasteful number, since it uses less digits than its factorization.

68228721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11757 (or 11754 counting only the distinct ones).

The product of its digits is 21504, while the sum is 36.

The square root of 68228721 is about 8260.0678568641. The cubic root of 68228721 is about 408.6226256318.

It can be divided in two parts, 682 and 28721, that added together give a triangular number (29403 = T₂₄₂).

The spelling of 68228721 in words is "sixty-eight million, two hundred twenty-eight thousand, seven hundred twenty-one".