66981738 has 8 divisors (see below), whose sum is σ = 133963488. Its totient is φ = 22327244.

The previous prime is 66981643. The next prime is 66981743. The reversal of 66981738 is 83718966.

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

66981738 is an admirable number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5581806 + ... + 5581817.

It is an arithmetic number, because the mean of its divisors is an integer number (16745436).

Almost surely, 2^66981738 is an apocalyptic number.

66981738 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66981738 is a wasteful number, since it uses less digits than its factorization.

66981738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11163628.

The product of its digits is 435456, while the sum is 48.

The square root of 66981738 is about 8184.2371666515. The cubic root of 66981738 is about 406.1179052031.

The spelling of 66981738 in words is "sixty-six million, nine hundred eighty-one thousand, seven hundred thirty-eight".