66491783 has 2 divisors, whose sum is σ = 66491784. Its totient is φ = 66491782.

The previous prime is 66491767. The next prime is 66491819. The reversal of 66491783 is 38719466.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66491783 - 2⁴ = 66491767 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66491723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33245891 + 33245892.

It is an arithmetic number, because the mean of its divisors is an integer number (33245892).

Almost surely, 2^66491783 is an apocalyptic number.

66491783 is a deficient number, since it is larger than the sum of its proper divisors (1).

66491783 is an equidigital number, since it uses as much as digits as its factorization.

66491783 is an evil number, because the sum of its binary digits is even.

The product of its digits is 217728, while the sum is 44.

The square root of 66491783 is about 8154.2493829904. The cubic root of 66491783 is about 405.1252632904.

The spelling of 66491783 in words is "sixty-six million, four hundred ninety-one thousand, seven hundred eighty-three".