266213666 has 4 divisors (see below), whose sum is σ = 399320502. Its totient is φ = 133106832.

The previous prime is 266213653. The next prime is 266213677. The reversal of 266213666 is 666312662.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 666312662 = 2 ⋅333156331.

It can be written as a sum of positive squares in only one way, i.e., 196140025 + 70073641 = 14005^2 + 8371^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 66553415 + ... + 66553418.

Almost surely, 2^266213666 is an apocalyptic number.

266213666 is a deficient number, since it is larger than the sum of its proper divisors (133106836).

266213666 is a wasteful number, since it uses less digits than its factorization.

266213666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133106835.

The product of its digits is 93312, while the sum is 38.

The square root of 266213666 is about 16316.0554669320. The cubic root of 266213666 is about 643.2949103800.

The spelling of 266213666 in words is "two hundred sixty-six million, two hundred thirteen thousand, six hundred sixty-six".