66783919 has 2 divisors, whose sum is σ = 66783920. Its totient is φ = 66783918.

The previous prime is 66783911. The next prime is 66783923. The reversal of 66783919 is 91938766.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66783919 - 2³ = 66783911 is a prime.

It is a super-2 number, since 2×66783919² = 8920183673997122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66783911) 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 as a sum of consecutive naturals, namely, 33391959 + 33391960.

It is an arithmetic number, because the mean of its divisors is an integer number (33391960).

Almost surely, 2^66783919 is an apocalyptic number.

66783919 is a deficient number, since it is larger than the sum of its proper divisors (1).

66783919 is an equidigital number, since it uses as much as digits as its factorization.

66783919 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 489888, while the sum is 49.

The square root of 66783919 is about 8172.1428646347. The cubic root of 66783919 is about 405.7177112682.

The spelling of 66783919 in words is "sixty-six million, seven hundred eighty-three thousand, nine hundred nineteen".