66929721 has 8 divisors (see below), whose sum is σ = 89756160. Its totient is φ = 44361552.

The previous prime is 66929591. The next prime is 66929743. The reversal of 66929721 is 12792966.

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

It is not a de Polignac number, because 66929721 - 2¹¹ = 66927673 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66929791) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 63961 + ... + 64998.

It is an arithmetic number, because the mean of its divisors is an integer number (11219520).

Almost surely, 2^66929721 is an apocalyptic number.

It is an amenable number.

66929721 is a deficient number, since it is larger than the sum of its proper divisors (22826439).

66929721 is a wasteful number, since it uses less digits than its factorization.

66929721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129135.

The product of its digits is 81648, while the sum is 42.

The square root of 66929721 is about 8181.0586723235. The cubic root of 66929721 is about 406.0127496461.

The spelling of 66929721 in words is "sixty-six million, nine hundred twenty-nine thousand, seven hundred twenty-one".