666455549 has 4 divisors (see below), whose sum is σ = 679030236. Its totient is φ = 653880864.

The previous prime is 666455519. The next prime is 666455593. The reversal of 666455549 is 945554666.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 426422500 + 240033049 = 20650^2 + 15493^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-666455549 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 666455497 and 666455506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666455509) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6287264 + ... + 6287369.

It is an arithmetic number, because the mean of its divisors is an integer number (169757559).

Almost surely, 2^666455549 is an apocalyptic number.

It is an amenable number.

666455549 is a deficient number, since it is larger than the sum of its proper divisors (12574687).

666455549 is a wasteful number, since it uses less digits than its factorization.

666455549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12574686.

The product of its digits is 3888000, while the sum is 50.

The square root of 666455549 is about 25815.8003749642. The cubic root of 666455549 is about 873.4882408659.

The spelling of 666455549 in words is "six hundred sixty-six million, four hundred fifty-five thousand, five hundred forty-nine".