1266131666 has 4 divisors (see below), whose sum is σ = 1899197502. Its totient is φ = 633065832.

The previous prime is 1266131641. The next prime is 1266131687. The reversal of 1266131666 is 6661316621.

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., 953018641 + 313113025 = 30871^2 + 17695^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 316532915 + ... + 316532918.

Almost surely, 2^1266131666 is an apocalyptic number.

1266131666 is a deficient number, since it is larger than the sum of its proper divisors (633065836).

1266131666 is an equidigital number, since it uses as much as digits as its factorization.

1266131666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 633065835.

The product of its digits is 46656, while the sum is 38.

The square root of 1266131666 is about 35582.7439357900. The cubic root of 1266131666 is about 1081.8315019440.

The spelling of 1266131666 in words is "one billion, two hundred sixty-six million, one hundred thirty-one thousand, six hundred sixty-six".