66781673 has 8 divisors (see below), whose sum is σ = 79640448. Its totient is φ = 54752544.

The previous prime is 66781601. The next prime is 66781679. The reversal of 66781673 is 37618766.

It is a happy number.

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

It is not a de Polignac number, because 66781673 - 2¹² = 66777577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66781679) 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, 207236 + ... + 207557.

It is an arithmetic number, because the mean of its divisors is an integer number (9955056).

Almost surely, 2^66781673 is an apocalyptic number.

It is an amenable number.

66781673 is a deficient number, since it is larger than the sum of its proper divisors (12858775).

66781673 is a wasteful number, since it uses less digits than its factorization.

66781673 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 414823.

The product of its digits is 254016, while the sum is 44.

The square root of 66781673 is about 8172.0054454216. The cubic root of 66781673 is about 405.7131630066.

The spelling of 66781673 in words is "sixty-six million, seven hundred eighty-one thousand, six hundred seventy-three".