266165506 has 4 divisors (see below), whose sum is σ = 399248262. Its totient is φ = 133082752.

The previous prime is 266165503. The next prime is 266165507. The reversal of 266165506 is 605561662.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 605561662 = 2 ⋅302780831.

It can be written as a sum of positive squares in only one way, i.e., 265853025 + 312481 = 16305^2 + 559^2 .

It is not an unprimeable number, because it can be changed into a prime (266165503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 66541375 + ... + 66541378.

Almost surely, 2^266165506 is an apocalyptic number.

266165506 is a deficient number, since it is larger than the sum of its proper divisors (133082756).

266165506 is a wasteful number, since it uses less digits than its factorization.

266165506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133082755.

The product of its (nonzero) digits is 64800, while the sum is 37.

The square root of 266165506 is about 16314.5795532707. The cubic root of 266165506 is about 643.2561157885.

The spelling of 266165506 in words is "two hundred sixty-six million, one hundred sixty-five thousand, five hundred six".