666143554 has 4 divisors (see below), whose sum is σ = 999215334. Its totient is φ = 333071776.

The previous prime is 666143537. The next prime is 666143603. The reversal of 666143554 is 455341666.

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

It can be written as a sum of positive squares in only one way, i.e., 515517025 + 150626529 = 22705^2 + 12273^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166535887 + ... + 166535890.

Almost surely, 2^666143554 is an apocalyptic number.

666143554 is a deficient number, since it is larger than the sum of its proper divisors (333071780).

666143554 is a wasteful number, since it uses less digits than its factorization.

666143554 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333071779.

The product of its digits is 259200, while the sum is 40.

The square root of 666143554 is about 25809.7569535244. The cubic root of 666143554 is about 873.3519144439.

The spelling of 666143554 in words is "six hundred sixty-six million, one hundred forty-three thousand, five hundred fifty-four".