66939786 has 12 divisors (see below), whose sum is σ = 145036242. Its totient is φ = 22313256.

The previous prime is 66939739. The next prime is 66939787. The reversal of 66939786 is 68793966.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 66928761 + 11025 = 8181^2 + 105^2 .

It is not an unprimeable number, because it can be changed into a prime (66939787) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 1859421 + ... + 1859456.

Almost surely, 2^66939786 is an apocalyptic number.

66939786 is an abundant number, since it is smaller than the sum of its proper divisors (78096456).

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

66939786 is a wasteful number, since it uses less digits than its factorization.

66939786 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3718885 (or 3718882 counting only the distinct ones).

The product of its digits is 2939328, while the sum is 54.

The square root of 66939786 is about 8181.6737896350. The cubic root of 66939786 is about 406.0331009113.

The spelling of 66939786 in words is "sixty-six million, nine hundred thirty-nine thousand, seven hundred eighty-six".