726553666 has 4 divisors (see below), whose sum is σ = 1089830502. Its totient is φ = 363276832.

The previous prime is 726553643. The next prime is 726553669. The reversal of 726553666 is 666355627.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 666355627 = 7 ⋅95193661.

It can be written as a sum of positive squares in only one way, i.e., 375778225 + 350775441 = 19385^2 + 18729^2 .

It is not an unprimeable number, because it can be changed into a prime (726553669) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 181638415 + ... + 181638418.

Almost surely, 2^726553666 is an apocalyptic number.

726553666 is a deficient number, since it is larger than the sum of its proper divisors (363276836).

726553666 is a wasteful number, since it uses less digits than its factorization.

726553666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 363276835.

The product of its digits is 1360800, while the sum is 46.

The square root of 726553666 is about 26954.6594487855. The cubic root of 726553666 is about 898.9921499865.

The spelling of 726553666 in words is "seven hundred twenty-six million, five hundred fifty-three thousand, six hundred sixty-six".