66994789 has 2 divisors, whose sum is σ = 66994790. Its totient is φ = 66994788.

The previous prime is 66994783. The next prime is 66994799. The reversal of 66994789 is 98749966.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64272289 + 2722500 = 8017^2 + 1650^2 .

It is a cyclic number.

It is not a de Polignac number, because 66994789 - 2⁵ = 66994757 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66994783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33497394 + 33497395.

It is an arithmetic number, because the mean of its divisors is an integer number (33497395).

Almost surely, 2^66994789 is an apocalyptic number.

It is an amenable number.

66994789 is a deficient number, since it is larger than the sum of its proper divisors (1).

66994789 is an equidigital number, since it uses as much as digits as its factorization.

66994789 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5878656, while the sum is 58.

The square root of 66994789 is about 8185.0344531957. The cubic root of 66994789 is about 406.1442800566.

The spelling of 66994789 in words is "sixty-six million, nine hundred ninety-four thousand, seven hundred eighty-nine".