66139723 has 8 divisors (see below), whose sum is σ = 71290800. Its totient is φ = 60997728.

The previous prime is 66139687. The next prime is 66139729. The reversal of 66139723 is 32793166.

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 66139723 - 2⁹ = 66139211 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66139729) 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, 25668 + ... + 28126.

It is an arithmetic number, because the mean of its divisors is an integer number (8911350).

Almost surely, 2^66139723 is an apocalyptic number.

66139723 is a deficient number, since it is larger than the sum of its proper divisors (5151077).

66139723 is a wasteful number, since it uses less digits than its factorization.

66139723 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4541.

The product of its digits is 40824, while the sum is 37.

The square root of 66139723 is about 8132.6332144023. The cubic root of 66139723 is about 404.4089799344.

The spelling of 66139723 in words is "sixty-six million, one hundred thirty-nine thousand, seven hundred twenty-three".