68070721 has 4 divisors (see below), whose sum is σ = 68246100. Its totient is φ = 67895344.

The previous prime is 68070697. The next prime is 68070773. The reversal of 68070721 is 12707086.

It is a happy number.

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 37699600 + 30371121 = 6140^2 + 5511^2 .

It is a cyclic number.

It is not a de Polignac number, because 68070721 - 2¹¹ = 68068673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68070781) 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, 87106 + ... + 87883.

It is an arithmetic number, because the mean of its divisors is an integer number (17061525).

Almost surely, 2^68070721 is an apocalyptic number.

It is an amenable number.

68070721 is a deficient number, since it is larger than the sum of its proper divisors (175379).

68070721 is a wasteful number, since it uses less digits than its factorization.

68070721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175378.

The product of its (nonzero) digits is 4704, while the sum is 31.

The square root of 68070721 is about 8250.4982273800. The cubic root of 68070721 is about 408.3069605439.

The spelling of 68070721 in words is "sixty-eight million, seventy thousand, seven hundred twenty-one".