66783939 has 16 divisors (see below), whose sum is σ = 94453632. Its totient is φ = 41827968.

The previous prime is 66783923. The next prime is 66783947. The reversal of 66783939 is 93938766.

It is a happy number.

It is not a de Polignac number, because 66783939 - 2⁴ = 66783923 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a junction number, because it is equal to n+sod(n) for n = 66783891 and 66783900.

It is not an unprimeable number, because it can be changed into a prime (66783919) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 44292 + ... + 45774.

It is an arithmetic number, because the mean of its divisors is an integer number (5903352).

Almost surely, 2^66783939 is an apocalyptic number.

66783939 is a deficient number, since it is larger than the sum of its proper divisors (27669693).

66783939 is a wasteful number, since it uses less digits than its factorization.

66783939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2386.

The product of its digits is 1469664, while the sum is 51.

The square root of 66783939 is about 8172.1440883039. The cubic root of 66783939 is about 405.7177517687.

The spelling of 66783939 in words is "sixty-six million, seven hundred eighty-three thousand, nine hundred thirty-nine".