266807991 has 8 divisors (see below), whose sum is σ = 364017280. Its totient is φ = 173735352.

The previous prime is 266807987. The next prime is 266807993. The reversal of 266807991 is 199708662.

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

It is not a de Polignac number, because 266807991 - 2² = 266807987 is a prime.

It is a super-2 number, since 2×266807991² = 142373008122912162, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 266807991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (266807993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1034011 + ... + 1034268.

It is an arithmetic number, because the mean of its divisors is an integer number (45502160).

Almost surely, 2^266807991 is an apocalyptic number.

266807991 is a deficient number, since it is larger than the sum of its proper divisors (97209289).

266807991 is a wasteful number, since it uses less digits than its factorization.

266807991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2068325.

The product of its (nonzero) digits is 326592, while the sum is 48.

The square root of 266807991 is about 16334.2582017060. The cubic root of 266807991 is about 643.7732756092.

The spelling of 266807991 in words is "two hundred sixty-six million, eight hundred seven thousand, nine hundred ninety-one".