67939721 has 8 divisors (see below), whose sum is σ = 70414920. Its totient is φ = 65473408.

The previous prime is 67939681. The next prime is 67939741. The reversal of 67939721 is 12793976.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 3763600 + 64176121 = 1940^2 + 8011^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 67939721 - 2⁶ = 67939657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (67939741) 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 7 ways as a sum of consecutive naturals, for example, 15995 + ... + 19791.

It is an arithmetic number, because the mean of its divisors is an integer number (8801865).

Almost surely, 2^67939721 is an apocalyptic number.

It is an amenable number.

67939721 is a deficient number, since it is larger than the sum of its proper divisors (2475199).

67939721 is a wasteful number, since it uses less digits than its factorization.

67939721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4443.

The product of its digits is 142884, while the sum is 44.

The square root of 67939721 is about 8242.5554896525. Note that the first 3 decimals coincide. The cubic root of 67939721 is about 408.0448676308.

The spelling of 67939721 in words is "sixty-seven million, nine hundred thirty-nine thousand, seven hundred twenty-one".