266663991 has 8 divisors (see below), whose sum is σ = 387874944. Its totient is φ = 161614520.

The previous prime is 266663987. The next prime is 266664017. The reversal of 266663991 is 199366662.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 266663991 - 2² = 266663987 is a prime.

It is a super-2 number, since 2×266663991² = 142219368192096162, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 266663991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (266663911) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4040331 + ... + 4040396.

It is an arithmetic number, because the mean of its divisors is an integer number (48484368).

Almost surely, 2^266663991 is an apocalyptic number.

266663991 is a deficient number, since it is larger than the sum of its proper divisors (121210953).

266663991 is a wasteful number, since it uses less digits than its factorization.

266663991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8080741.

The product of its digits is 629856, while the sum is 48.

The square root of 266663991 is about 16329.8496931233. The cubic root of 266663991 is about 643.6574369568.

The spelling of 266663991 in words is "two hundred sixty-six million, six hundred sixty-three thousand, nine hundred ninety-one".