666783773 has 2 divisors, whose sum is σ = 666783774. Its totient is φ = 666783772.

The previous prime is 666783709. The next prime is 666783797. The reversal of 666783773 is 377387666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 543729124 + 123054649 = 23318^2 + 11093^2 .

It is a cyclic number.

It is not a de Polignac number, because 666783773 - 2⁶ = 666783709 is a prime.

It is a super-2 number, since 2×666783773² = 889201199872231058, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666783703) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333391886 + 333391887.

It is an arithmetic number, because the mean of its divisors is an integer number (333391887).

Almost surely, 2^666783773 is an apocalyptic number.

It is an amenable number.

666783773 is a deficient number, since it is larger than the sum of its proper divisors (1).

666783773 is an equidigital number, since it uses as much as digits as its factorization.

666783773 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5334336, while the sum is 53.

The square root of 666783773 is about 25822.1566295304. The cubic root of 666783773 is about 873.6316126441.

The spelling of 666783773 in words is "six hundred sixty-six million, seven hundred eighty-three thousand, seven hundred seventy-three".