66658739 has 4 divisors (see below), whose sum is σ = 76181424. Its totient is φ = 57136056.

The previous prime is 66658723. The next prime is 66658747. The reversal of 66658739 is 93785666.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66658739 - 2⁴ = 66658723 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66658759) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4761332 + ... + 4761345.

It is an arithmetic number, because the mean of its divisors is an integer number (19045356).

Almost surely, 2^66658739 is an apocalyptic number.

66658739 is a deficient number, since it is larger than the sum of its proper divisors (9522685).

66658739 is an equidigital number, since it uses as much as digits as its factorization.

66658739 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9522684.

The product of its digits is 1632960, while the sum is 50.

The square root of 66658739 is about 8164.4803263894. The cubic root of 66658739 is about 405.4640598444.

The spelling of 66658739 in words is "sixty-six million, six hundred fifty-eight thousand, seven hundred thirty-nine".