66993786 has 12 divisors (see below), whose sum is σ = 145153242. Its totient is φ = 22331256.

The previous prime is 66993781. The next prime is 66993803. The reversal of 66993786 is 68739966.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 66928761 + 65025 = 8181^2 + 255^2 .

It is a super-2 number, since 2×66993786² = 8976334725227592, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66993781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1860921 + ... + 1860956.

Almost surely, 2^66993786 is an apocalyptic number.

66993786 is an abundant number, since it is smaller than the sum of its proper divisors (78159456).

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

66993786 is a wasteful number, since it uses less digits than its factorization.

66993786 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3721885 (or 3721882 counting only the distinct ones).

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

The square root of 66993786 is about 8184.9731826073. The cubic root of 66993786 is about 406.1422532087.

The spelling of 66993786 in words is "sixty-six million, nine hundred ninety-three thousand, seven hundred eighty-six".